California Water Service (CWT) 10-Q 26 Oct 23 2023 Q3 Quarterly report Financial data

Cover

Cover	9 Months Ended
	Sep. 30, 2023 shares
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2023
Document Transition Report	false
Entity File Number	1-13883
Entity Registrant Name	CALIFORNIA WATER SERVICE GROUP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	77-0448994
Entity Address, Address Line One	1720 North First Street
Entity Address, City or Town	San Jose
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95112
City Area Code	408
Local Phone Number	367-8200
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	CWT
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding	57,711,000
Entity Central Index Key	0001035201
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Utility plant:
Utility plant	$ 4,817,310	$ 4,536,272
Less accumulated depreciation and amortization	(1,568,986)	(1,477,402)
Net utility plant	3,248,324	3,058,870
Current assets:
Cash and cash equivalents	34,735	62,100
Restricted cash	34,315	22,925
Receivables:
Customers, net	78,561	55,079
Regulatory balancing accounts	52,918	66,826
Other, net	21,766	20,932
Unbilled revenue, net	45,178	33,140
Materials and supplies	15,454	12,564
Taxes, prepaid expenses, and other assets	19,355	21,969
Total current assets	302,282	295,535
Other assets:
Regulatory assets	265,630	283,620
Goodwill	36,814	36,814
Other assets	188,311	175,913
Total other assets	490,755	496,347
TOTAL ASSETS	4,041,361	3,850,752
Capitalization:
Common stock, $0.01 par value; 136,000 shares authorized, 57,711 and 55,598 outstanding in 2023 and 2022, respectively	577	556
Additional paid-in capital	875,640	760,336
Retained earnings	534,451	556,698
Noncontrolling interests	4,327	4,804
Total equity	1,414,995	1,322,394
Long-term debt, net	1,051,846	1,052,487
Total capitalization	2,466,841	2,374,881
Current liabilities:
Current maturities of long-term debt, net	1,823	3,310
Short-term borrowings	115,000	70,000
Accounts payable	152,869	140,986
Regulatory balancing accounts	26,458	12,240
Accrued interest	17,589	6,490
Accrued expenses and other liabilities	67,401	61,624
Total current liabilities	381,140	294,650
Deferred income taxes	332,869	330,251
Pension	80,674	78,443
Regulatory liabilities and other	289,131	287,294
Advances for construction	200,716	199,832
Contributions in aid of construction	289,990	285,401
Commitments and contingencies (Note 10)
TOTAL CAPITALIZATION AND LIABILITIES	$ 4,041,361	$ 3,850,752

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2023	Dec. 31, 2022	Jul. 26, 2022	Jul. 25, 2022
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	136,000,000	136,000,000	136,000,000	68,000,000
Common stock, shares outstanding (in shares)	57,711,000	55,598,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Statement [Abstract]
Operating revenue	$ 254,976	$ 266,307	$ 580,120	$ 645,494
Operations:
Water production costs	92,347	88,750	218,222	221,195
Administrative and general	34,216	33,328	105,177	99,425
Other operations	32,331	26,676	74,758	81,945
Maintenance	8,930	8,433	24,063	23,389
Depreciation and amortization	29,897	28,844	89,636	86,387
Income tax expense (benefit)	3,949	5,890	(1,366)	5,927
Property and other taxes	9,832	9,440	27,731	25,853
Total operating expenses	211,502	201,361	538,221	544,121
Net operating income	43,474	64,946	41,899	101,373
Other income and expenses:
Non-regulated revenue	4,535	4,573	13,643	16,772
Non-regulated expenses	(5,992)	(6,905)	(11,224)	(22,432)
Other components of net periodic benefit credit	4,776	3,737	14,753	11,516
Allowance for equity funds used during construction	1,387	1,004	4,146	3,021
Income tax expense on other income and expenses	(1,063)	(353)	(4,302)	(1,210)
Net other income	3,643	2,056	17,016	7,667
Interest expense:
Interest expense	13,482	11,891	39,791	34,972
Allowance for borrowed funds used during construction	(690)	(572)	(2,314)	(1,724)
Net interest expense	12,792	11,319	37,477	33,248
Net income	34,325	55,683	21,438	75,792
Net loss attributable to noncontrolling interests	(113)	(189)	(345)	(650)
Net income attributable to California Water Service Group	$ 34,438	$ 55,872	$ 21,783	$ 76,442
Earnings per share of common stock:
Basic (in dollars per share)	$ 0.60	$ 1.03	$ 0.38	$ 1.41
Diluted (in dollars per share)	$ 0.60	$ 1.03	$ 0.38	$ 1.41
Weighted average shares outstanding:
Basic (in shares)	57,704	54,007	56,695	54,063
Diluted (in shares)	57,740	54,042	56,731	54,104

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Operating activities:
Net income	$ 21,438	$ 75,792
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	91,131	88,488
Change in value of life insurance contracts	(712)	9,319
Allowance for equity funds used during construction	(4,146)	(3,021)
Changes in operating assets and liabilities:
Receivables and unbilled revenue	(6,063)	(67,277)
Water Arrearages Payment Program cash received	0	20,836
Water Arrearages Payment Program cash returned	0	(3,609)
Accounts payable	8,865	1,055
Other current assets	(356)	3,293
Other current liabilities	14,791	22,447
Other changes in noncurrent assets and liabilities	18,560	52,518
Net cash provided by operating activities	143,508	199,841
Investing activities:
Utility plant expenditures	(274,129)	(222,088)
Life insurance proceeds	0	6,688
Purchase of life insurance contracts	(2,681)	(6,688)
Asset acquisitions	(2,816)	(6,319)
Net cash used in investing activities	(279,626)	(228,407)
Financing activities:
Short-term borrowings, net of issuance costs of $1,552 for 2023 and $0 for 2022	163,448	95,000
Repayment of short-term borrowings	(120,000)	(60,000)
Repayment of long-term debt	(1,546)	(1,575)
Advances and contributions in aid of construction	16,707	18,785
Refunds of advances for construction	(6,881)	(6,854)
Repurchase of common stock	(1,740)	(1,891)
Issuance of common stock, net	114,473	58,709
Dividends paid	(44,030)	(40,471)
Distribution to noncontrolling interest	(288)	(348)
Net cash provided by financing activities	120,143	61,355
Change in cash, cash equivalents, and restricted cash	(15,975)	32,789
Cash, cash equivalents, and restricted cash at beginning of period	85,025	80,653
Cash, cash equivalents, and restricted cash at end of period	69,050	113,442
Supplemental information:
Cash paid for interest (net of amounts capitalized)	25,945	19,178
Supplemental disclosure of non-cash activities:
Accrued payables for investments in utility plant	51,435	61,944
Utility plant contribution by developers	$ 19,979	$ 15,476

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Statement of Cash Flows [Abstract]
Payments of debt issuance costs	$ 1,552	$ 0

Organization and Operations and

Organization and Operations and Basis of Presentation	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Operations and Basis of Presentation	Organization and Operations and Basis of Presentation California Water Service Group (Company) is a holding company that provides water utility and other related services in California, Washington, New Mexico, Hawaii, and Texas through its wholly-owned and non-wholly owned subsidiaries. California Water Service Company (Cal Water), Washington Water Service Company (Washington Water), New Mexico Water Service Company (New Mexico Water), and Hawaii Water Service Company, Inc. (Hawaii Water), provide regulated utility services under the rules and regulations of their respective state’s regulatory commissions (jointly referred to as the Commissions). CWS Utility Services and HWS Utility Services LLC provide non-regulated water utility and utility-related services. TWSC, Inc. (Texas Water) holds a majority investment in a holding company that owns and operates regulated and contracted wastewater utilities. The Company operates in one reportable segment, providing water and water related utility services. Basis of Presentation The unaudited condensed consolidated interim financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) for interim financial information and in accordance with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X promulgated by the Securities and Exchange Commission (SEC) and therefore do not contain all of the information and footnotes required by GAAP and the SEC for annual financial statements. Interim financial information includes the Company's accounts and those of its wholly and non-wholly owned subsidiaries. The non-wholly owned subsidiary was consolidated using the voting interest model as the Company owns a majority of the non-wholly owned subsidiary's voting interests. The interim unaudited condensed consolidated financial statements should be read in conjunction with the Company’s consolidated financial statements included in its Annual Report on Form 10-K for the year ended December 31, 2022 as filed with the SEC on March 1, 2023. The preparation of the Company’s unaudited condensed consolidated interim financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the balance sheet dates and the reported amounts of revenues and expenses for the periods presented. These include, but are not limited to, estimates and assumptions used in determining the Company’s regulatory asset and liability balances based upon probability assessments of regulatory recovery, revenues earned but not yet billed, asset retirement obligations, allowance for credit losses, pension and other employee benefit plan liabilities, and income tax-related assets and liabilities. Actual results could materially differ from these estimates. In the opinion of management, the accompanying unaudited condensed consolidated interim financial statements reflect all adjustments, consisting of normal recurring transactions that are necessary to provide a fair presentation of the results for the periods covered. Due to the seasonal nature of the water business, the results for interim periods are not indicative of the results for a 12-month period. Revenue and income are generally higher in the warm, dry summer months when water usage and sales are greater. Revenue and income are generally lower in the winter months when cooler temperatures and rainfall curtail water usage and sales. Noncontrolling Interests Noncontrolling interests in the Company’s condensed consolidated financial statements represents a 5.5% interest not owned by Texas Water in a consolidated subsidiary. Since the Company controls this subsidiary, its financial statements are consolidated with those of the Company, and the noncontrolling owner’s 5.5% share of the subsidiary’s net assets and results of operations is deducted and reported as noncontrolling interests on the condensed consolidated balance sheet and as net loss attributable to noncontrolling interests in the condensed consolidated statement of operations. The Company reports noncontrolling interests in consolidated entities as a component of equity separate from the Company’s equity. The Company’s net income attributable to California Water Service Group excludes the net loss attributable to the noncontrolling interests.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Operating revenue The following tables disaggregate the Company’s operating revenue by source for the three and nine months ended September 30, 2023 and 2022: Three Months Ended September 30 2023 2022 Revenue from contracts with customers $ 253,337 $ 238,268 Regulatory balancing account revenue 1,639 28,039 Total operating revenue $ 254,976 $ 266,307 Nine Months Ended September 30 2023 2022 Revenue from contracts with customers $ 592,768 $ 595,860 Regulatory balancing account revenue (12,648) 49,634 Total operating revenue $ 580,120 $ 645,494 Revenue from contracts with customers The Company principally generates operating revenue from contracts with customers by providing regulated water and wastewater services at tariff-rates authorized by the Commissions in the states in which they operate and non-regulated water and wastewater services at rates authorized by contracts with government agencies. Revenue from contracts with customers reflects amounts billed for the volume of consumption at authorized per unit rates, for a service charge, and for other authorized charges. The Company satisfies its performance obligation to provide water and wastewater services over time as services are rendered. The Company applies the invoice practical expedient and recognizes revenue from contracts with customers in the amount for which the Company has a right to invoice. The Company has a right to invoice for the volume of consumption, for the service charge, and for other authorized charges. The measurement of sales to customers is generally based on the reading of their meters, which occurs on a systematic basis throughout the month. At the end of each month, the Company estimates consumption since the date of the last meter reading and the corresponding unbilled revenue is recognized. The estimate is based upon the number of unbilled days that month and the average daily customer billing rate from the previous month (which fluctuates based upon customer usage). Contract terms are generally short-term and at will by customers and, as a result, no separate financing component is recognized for the Company's collections from customers, which generally require payment within 30 days of billing. The Company applies judgment, based principally on historical payment experience, in estimating its customers’ ability to pay. Certain customers are not billed for volumetric consumption, but are instead billed a flat rate at the beginning of each monthly service period. The amount billed is initially deferred and subsequently recognized over the monthly service period, as the performance obligation is satisfied. The deferred revenue balance or contract liability, which is included in "accrued expenses and other liabilities" on the unaudited condensed consolidated balance sheets, is inconsequential. In the following tables, revenue from contracts with customers is disaggregated by class of customers for the three and nine months ended September 30, 2023 and 2022: Three Months Ended September 30 2023 2022 Residential $ 150,031 $ 140,585 Business 47,707 44,031 Multiple residential 18,778 17,333 Industrial 8,165 8,086 Public authorities 14,522 13,441 Other (a) 14,134 14,792 Total revenue from contracts with customers $ 253,337 $ 238,268 Nine Months Ended September 30 2023 2022 Residential $ 342,806 $ 348,965 Business 117,527 115,472 Multiple residential 50,280 48,343 Industrial 19,672 20,174 Public authorities 29,938 31,310 Other (a) 32,545 31,596 Total revenue from contracts with customers $ 592,768 $ 595,860 (a) Other includes accrued unbilled revenue. Regulatory balancing account revenue Regulatory balancing account revenue is revenue related to revenue mechanisms authorized in California by the California Public Utilities Commission (CPUC), which allow the Company to recognize revenue when it is objectively determinable, probable of recovery and expected to be collected within 24 months following the end of the accounting period, and are not considered contracts with customers and are not included in the total revenue from contracts with customers in the table above. To the extent that revenue is estimated to be collectible beyond 24 months, recognition is deferred. Due to a delay in resolution of the most recent Cal Water General Rate Case (GRC) filing (2021 GRC Filing), the Company did not recognize a benefit from any regulatory revenue mechanisms in the first nine months of 2023. For 2022, the Company's authorized regulatory revenue mechanisms included the Water Revenue Adjustment Mechanism (WRAM). The WRAM decoupled revenue from the volume of the sales and allowed the Company to recognize the adopted level of volumetric revenues. The variance between adopted volumetric revenues and actual billed volumetric revenues for metered accounts was recorded as regulatory balancing account revenue. The WRAM concluded on December 31, 2022. Regulatory balancing accounts also includes revenue that is recognized for balancing accounts when it is probable that future recovery of previously incurred costs or future refunds that are to be credited to customers will occur through the ratemaking process. These mechanisms, such as the Modified Cost Balancing Account (MCBA), Conservation Expense Balancing Account (CEBA), Pension Cost Balancing Account (PCBA), and Health Cost Balancing Account (HCBA), generally provide for recovery of the adopted levels of expenses for purchased water, purchased power, pump taxes, water conservation program costs, pension, and health care. Variances between adopted and actual costs were recorded as regulatory balancing account revenue in 2022. In 2023, in connection with the CPUC's decision to discontinue the use of the WRAM, the variances for CEBA, HCBA, and PCBA are recorded against the originating expense. The MCBA concluded on December 31, 2022. The CPUC issued a decision effective August 27, 2020 requiring that Class A companies submitting GRC filings after the effective date be (i) precluded from proposing the use of a full decoupling WRAM in their next GRCs and (ii) allowed the use of Monterey-Style Water Revenue Adjustment Mechanisms (MWRAM). In addition, the CPUC's decision allowed for Incremental Cost Balancing Accounts (ICBAs) to replace the MCBA. The MWRAM tracks the difference between the revenue received for actual metered sales through the tiered volumetric rate and the revenue that would have been received with the same actual metered sales if a uniform rate had been in effect. The ICBA tracks differences between the authorized per-unit prices of water production costs and actual per-unit prices of water production costs. Cal Water complied with this decision in its 2021 GRC Filing and expects the MWRAM and ICBAs to be approved and effective retroactive to January 1, 2023. For the first nine months of 2023, the Company did not record a regulatory asset or regulatory liability for the MWRAM or ICBAs. Non-regulated Revenue The following tables disaggregate the Company’s non-regulated revenue by source for the three and nine months ended September 30, 2023 and 2022: Three Months Ended September 30 2023 2022 Operating and maintenance revenue $ 2,918 $ 3,184 Other non-regulated revenue 972 720 Non-regulated revenue from contracts with customers 3,890 3,904 Lease revenue 645 669 Total non-regulated revenue $ 4,535 $ 4,573 Nine Months Ended September 30 2023 2022 Operating and maintenance revenue $ 9,229 $ 9,822 Other non-regulated revenue 2,553 4,951 Non-regulated revenue from contracts with customers 11,782 14,773 Lease revenue 1,861 1,999 Total non-regulated revenue $ 13,643 $ 16,772 Operating and maintenance services are provided for non-regulated water and wastewater systems owned by private companies and municipalities. The Company negotiates formal agreements with the customers, under which they provide operating, maintenance and customer billing services related to the customers’ water system. The formal agreements outline the fee schedule for the services provided. The agreements typically call for a fee-per-service or a flat-rate amount per month. The Company satisfies its performance obligation of providing operating and maintenance services over time as services are rendered; as a result, the Company employs the invoice practical expedient and recognizes revenue in the amount that it has the right to invoice. Contract terms are generally short-term and, as a result, no separate financing component is recognized for its collections from customers, which generally require payment within 30 days of billing. Other non-regulated revenue primarily relates to services for the design and installation of water mains and other water infrastructure for customers outside the regulated service areas and insurance program administration. During the first nine months of 2022, the Company recorded a gain of $2.7 million related to company owned life insurance. Lease revenue is not considered revenue from contracts with customers and is recognized following operating lease standards. The Company is the lessor in operating lease agreements with telecommunications companies under which cellular phone antennas are placed on the Company's property. Allowance for credit losses The Company measures expected credit losses for Customer Receivables, Other Receivables, and Unbilled Revenue on an aggregated level. These receivables are generally trade receivables due in one year or less or expected to be billed and collected in one year or less. The expected credit losses for Other Receivables and Unbilled Revenue are inconsequential. Customer receivables include receivables for water and wastewater services provided to residential customers, business, industrial, public authorities, and other customers. The expected credit losses for business, industrial, public authorities, and other customers are inconsequential. The overall risks related to the Company’s receivables are low as water and wastewater services are seen as essential services. The estimate for the allowance for credit losses is based on a historical loss ratio, in conjunction with a qualitative assessment of elements that impact the collectability of receivables to determine if the allowance for credit losses should be further adjusted. Management's assessment contemplates available current information such as changes in economic factors, regulatory matters, industry trends, payment options and programs available to customers, and the methods that the Company is able to utilize to ensure payment. The Company reviews its allowance for credit losses utilizing a quantitative assessment, which includes a trend analysis of customer billings and collections, agings by customer class, and unemployment rates. The Company also utilizes a qualitative assessment, which considers the future collectability on customer outstanding balances, management's estimate of the cash recovery, and a general assessment of the economic conditions in the locations the Company serves. Based on these assessments, the Company adjusts its allowance for credit losses. The following table presents the activity in the allowance for credit losses for the 9-month period ended September 30, 2023 and 12-month period ended December 31, 2022: Allowance for credit losses September 30, 2023 December 31, 2022 Beginning balance $ 5,629 $ 3,743 Provision for credit loss expense 3,274 5,887 Write-offs (4,527) (4,380) Recoveries 413 379 Total ending allowance balance $ 4,789 $ 5,629 Cash, Cash Equivalents, and Restricted Cash The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the Condensed Consolidated Balance Sheets that sum to the total of the same such amounts shown on the Condensed Consolidated Statements of Cash Flows (see Note 10 for further details on restricted cash): September 30, 2023 December 31, 2022 Cash and cash equivalents $ 34,735 $ 62,100 Restricted cash 34,315 22,925 Total cash, cash equivalents, and restricted cash shown in the statements of cash flows $ 69,050 $ 85,025

Stock-based Compensation

Stock-based Compensation	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Stock-based Compensation	Stock-based Compensation The Company's equity incentive plan was approved and amended by stockholders on April 27, 2005 and May 20, 2014, respectively. The Company is authorized to issue awards up to 2,000,000 shares of common stock. During the first nine months of 2023, the Company granted Restricted Stock Awards (RSAs) to Officers and members of the Board of Directors. An RSA share represents the right to receive a restricted share of the Company's common stock and is valued based on the fair market value of the Company's common stock at the date of grant. RSAs granted to Officers vest over 36 months with the first year cliff vesting. In general, RSAs granted to Board members vest at the end of 12 months. The RSAs are recognized as expense evenly over 36 months for shares granted to Officers and 12 months for shares granted to Board members. As of September 30, 2023, there was approximately $2.3 million of total unrecognized compensation cost related to RSAs. The cost is expected to be recognized over a weighted average period of 1.7 years. A summary of the status of outstanding RSAs as of September 30, 2023 is presented below: Number of RSA Shares Weighted-Average Grant-Date Fair Value RSAs at January 1, 2023 52,066 $ 55.77 Granted 43,834 55.38 Vested (37,210) 55.76 Forfeited (2,025) 55.59 RSAs at September 30, 2023 56,665 $ 55.50 During the first nine months of 2023, the Company granted performance-based Restricted Stock Units (RSUs) to Officers. An RSU represents the right to receive a share of the Company's common stock. Each award reflects a target number shares of common stock that may be issued to the award recipient. The 2023 awards may be earned upon the completion of a 3-year performance period. Whether RSUs are earned at the end of the performance period will be determined based on the achievement of certain performance objectives set by the Organization and Compensation Committee of the Board of Directors in connection with the issuance of the RSUs. The performance objectives are based on the Company's business plan covering the performance period. The performance objectives include achieving the budgeted return on equity, growth in stockholders' equity, and environmental, social, and governance targets. Depending on the results achieved during the 3-year performance period, the actual number of shares that a grant recipient receives at the end of the performance period may range from 0% to 200% of the target shares granted, provided that the grantee is continuously employed by the Company through the vesting date. If prior to the vesting date employment is terminated by reason of death, disability or normal retirement, then a pro rata portion of this award will vest. The RSUs are recognized as expense ratably over the 3-year performance period using the fair market value of the Company's common share at the date of grant and an estimated number of RSUs that will vest during the performance period. As of September 30, 2023, there was approximately $2.9 million of total unrecognized compensation cost related to RSUs. The cost is expected to be recognized over a weighted average period of 2.0 years. A summary of the status of outstanding RSUs as of September 30, 2023 is presented below: Number of RSU Shares Weighted-Average Grant-Date Fair Value RSUs at January 1, 2023 92,625 $ 54.06 Granted 43,633 55.48 Performance criteria adjustment 14,822 56.84 Vested (40,589) 56.84 Forfeited (14,309) 54.25 RSUs at September 30, 2023 96,182 $ 55.40 The Company has recorded compensation costs for the RSAs and RSUs that are included in administrative and general operating expenses in the amount of $1.2 million and $1.6 million for the three months ended September 30, 2023 and 2022, respectively. For the nine months ended September 30, 2023 and 2022, the Company has recorded compensation costs for the RSAs and RSUs in the amount of $2.7 million and $3.5 million, respectively.

Equity

Equity	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Equity	Equity On April 29, 2022, the Company entered into an equity distribution agreement to sell shares of its common stock having an aggregate gross sales price of up to $350.0 million from time to time depending on market conditions through an at-the-market equity program over the next three years. The Company intends to use the net proceeds from these sales, after deducting sales commissions and offering expenses, for general corporate purposes, which may include working capital, construction and acquisition expenditures, investments and repurchases, and redemptions of securities. The Company did not utilize its at-the-market equity program during the three months ended September 30, 2023. During the three months ended September 30, 2022, the Company sold 461,034 shares of common stock through its at-the-market equity program and raised proceeds of $26.9 million, net of $0.3 million in sales commissions. The Company sold 2,025,891 shares of common stock through its at-the-market equity program and raised proceeds of $112.7 million, net of $1.1 million in sales commissions paid during the nine months ended September 30, 2023. During the nine months ended September 30, 2022, the Company sold 1,035,668 shares of common stock through its at-the-market equity program and raised proceeds of $57.1 million, net of $0.6 million in sales commissions. As approved by the Company's stockholders at the 2022 Annual Meeting, effective July 26, 2022, the aggregate number of shares of common stock which the Company shall have authority to issue was increased from 68.0 million shares to 136.0 million shares. All of said 136.0 million shares shall be of one and the same series, namely shares with par value of $0.01 per share. The Company’s changes in total equity for the three and nine months ended September 30, 2023 and 2022 were as follows: Nine months ended September 30, 2023 Common Stock Additional Retained Noncontrolling Interests Total Equity Shares Amount (In thousands) Balance at January 1, 2023 55,598 $ 556 $ 760,336 $ 556,698 $ 4,804 $ 1,322,394 Net loss — — — (22,211) (123) (22,334) Issuance of common stock 420 4 18,922 — — 18,926 Repurchase of common stock (27) — (1,542) — — (1,542) Dividends paid on common stock ($0.2600 per share) — — — (14,456) — (14,456) Investment in business with noncontrolling interest — — (111) — 111 — Balance at March 31, 2023 55,991 560 777,605 520,031 4,792 1,302,988 Net income (loss) — — — 9,556 (109) 9,447 Issuance of common stock 1,713 17 96,482 — — 96,499 Repurchase of common stock (2) — (108) — — (108) Dividends paid on common stock ($0.2600 per share) — — — (14,571) — (14,571) Investment in business with noncontrolling interest — — (56) — 56 — Distribution to noncontrolling interest — — — — (288) (288) Balance at June 30, 2023 57,702 577 873,923 515,016 4,451 1,393,967 Net income (loss) — — — 34,438 (113) 34,325 Issuance of common stock 11 — 1,796 — — 1,796 Repurchase of common stock (2) — (90) — — (90) Dividends paid on common stock ($0.2600 per share) — — — (15,003) — (15,003) Investment in business with noncontrolling interest — — 11 — (11) — Balance at September 30, 2023 57,711 $ 577 $ 875,640 $ 534,451 $ 4,327 $ 1,414,995 Nine months ended September 30, 2022 Common Stock Additional Retained Noncontrolling Interests Total Equity Shares Amount (In thousands) Balance at January 1, 2022 53,716 $ 537 $ 651,121 $ 514,873 $ 5,386 $ 1,171,917 Net income (loss) — — — 1,086 (192) 894 Issuance of common stock 85 1 1,106 — — 1,107 Repurchase of common stock (28) — (1,674) — — (1,674) Dividends paid on common stock ($0.2500 per share) — — — (13,429) — (13,429) Investment in business with noncontrolling interest — — (54) — 54 — Balance at March 31, 2022 53,773 538 650,499 502,530 5,248 1,158,815 Net income (loss) — — — 19,484 (269) 19,215 Issuance of common stock 585 6 32,118 — — 32,124 Repurchase of common stock (2) — (111) — — (111) Dividends paid on common stock ($0.2500 per share) — — — (13,452) — (13,452) Investment in business with noncontrolling interest — — (153) — 153 — Distribution to noncontrolling interest — — — — (348) (348) Balance at June 30, 2022 54,356 544 682,353 508,562 4,784 1,196,243 Net income (loss) — — — 55,872 (189) 55,683 Issuance of common stock 470 4 29,034 — — 29,038 Repurchase of common stock (2) — (105) — — (105) Dividends paid on common stock ($0.2500 per share) — — — (13,590) — (13,590) Investment in business with noncontrolling interest — — (278) — 278 — Balance at September 30, 2022 54,824 $ 548 $ 711,004 $ 550,844 $ 4,873 $ 1,267,269

Earnings Per Share of Common St

Earnings Per Share of Common Stock	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Earnings Per Share of Common Stock	Earnings Per Share of Common Stock The computations of basic and diluted earnings per share of common stock are noted in the tables below. Basic earnings per share of common stock is computed by dividing the net income attributable to California Water Service Group by the weighted average number of common shares outstanding during the period. RSAs are included in the weighted average common shares outstanding because the shares have all the same voting and dividend rights as issued and unrestricted common stock. Three Months Ended September 30 2023 2022 (In thousands, except per share data) Net income $ 34,325 $ 55,683 Net loss attributable to noncontrolling interests $ (113) $ (189) Net income attributable to California Water Service Group $ 34,438 $ 55,872 Weighted average common shares outstanding, basic 57,704 54,007 Weighted average common shares outstanding, dilutive 57,740 54,042 Earnings per share of common stock - basic $ 0.60 $ 1.03 Earnings per share of common stock - diluted $ 0.60 $ 1.03 Nine Months Ended September 30 2023 2022 (In thousands, except per share data) Net income $ 21,438 $ 75,792 Net loss attributable to noncontrolling interests $ (345) $ (650) Net income attributable to California Water Service Group $ 21,783 $ 76,442 Weighted average common shares outstanding, basic 56,695 54,063 Weighted average common shares outstanding, dilutive 56,731 54,104 Earnings per share of common stock - basic $ 0.38 $ 1.41 Earnings per share of common stock - diluted $ 0.38 $ 1.41

Pension Plan and Other Postreti

Pension Plan and Other Postretirement Benefits	9 Months Ended
	Sep. 30, 2023
Retirement Benefits [Abstract]
Pension Plan and Other Postretirement Benefits	Pension Plan and Other Postretirement Benefits The Company provides a qualified, defined-benefit, non-contributory pension plan for substantially all employees. The Company makes annual contributions to fund amounts accrued for the qualified pension plan. The Company also maintains an unfunded, non-qualified, supplemental executive retirement plan. The costs of the plans are charged to expense or are capitalized in utility plant as appropriate. The Company offers medical, dental, vision, and life insurance benefits for retirees and their spouses and dependents. Participants are required to pay a premium, which offsets a portion of the cost. Cash contributions made by the Company to the pension plans were $2.9 million and $12.4 million for the nine months ended September 30, 2023 and 2022, respectively. Cash contributions made by the Company to the other postretirement benefit plans were $0.2 million and $0.5 million for the nine months ended September 30, 2023 and 2022, respectively. The total 2023 estimated cash contributions to the pension plans and other postretirement benefits plans are expected to be approximately $2.9 million and $0.2 million, respectively. The following tables list components of net periodic benefit costs for the pension plans and other postretirement benefits. The data listed under “pension plan” includes the qualified pension plan and the non-qualified supplemental executive retirement plan. The data listed under “other benefits” is for all other postretirement benefits. Three Months Ended September 30 Pension Plan Other Benefits 2023 2022 2023 2022 Service cost $ 6,046 $ 9,235 $ 1,126 $ 1,683 Interest cost 8,746 6,329 1,297 1,008 Expected return on plan assets (13,421) (11,307) (2,636) (2,482) Amortization of prior service cost 131 242 39 39 Recognized net actuarial (gain) loss (637) 999 (581) (228) Net periodic benefit cost (credit) $ 865 $ 5,498 $ (755) $ 20 Nine Months Ended September 30 Pension Plan Other Benefits 2023 2022 2023 2022 Service cost $ 18,137 $ 27,704 $ 3,379 $ 5,048 Interest cost 26,238 18,986 3,892 3,024 Expected return on plan assets (40,263) (33,920) (7,907) (7,445) Amortization of prior service cost 394 727 116 117 Recognized net actuarial (gain) loss (1,911) 2,997 (1,744) (685) Net periodic benefit cost (credit) $ 2,595 $ 16,494 $ (2,264) $ 59 Service cost portion of the pension plan and other postretirement benefits is recognized in "administrative and general" expenses within the Condensed Consolidated Statements of Operations. Other components of net periodic benefit costs include interest costs, expected return on plan assets, amortization of prior service costs, and recognized net actuarial loss and are reported together as "other components of net periodic benefit cost" within the Condensed Consolidated Statements of Operations.

Short-term and Long-term Borrow

Short-term and Long-term Borrowings	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Short-term and Long-term Borrowings	Short-term and Long-term Borrowings On March 31, 2023, the Company and Cal Water entered into syndicated credit agreements, which provide for unsecured revolving credit facilities of up to an initial aggregate amount of $600.0 million for a term of five years. The Company and subsidiaries that it designates may borrow up to $200.0 million under the Company’s revolving credit facility (the Company facility). Cal Water may borrow up to $400.0 million under its revolving credit facility (the Cal Water facility). Additionally, the credit facilities may be increased by up to an incremental $150.0 million under the Cal Water facility and $50.0 million under the Company facility, subject in each case to certain conditions. At the Company’s or Cal Water's option, as applicable, borrowings under the Company and Cal Water facilities, as applicable, will bear interest annually at a rate equal to (i) the base rate, plus an applicable margin of 0.00% to 0.250%, depending on the Company and its subsidiaries' consolidated total capitalization ratio, or (ii) Term SOFR, plus an applicable margin of 0.800% to 1.250%, depending on the Company and its subsidiaries' consolidated total capitalization ratio. The Company and Cal Water facilities contain affirmative and negative covenants and events of default customary for credit facilities of this type including, among other things, limitations and prohibitions relating to additional indebtedness, liens, mergers, and asset sales. Also, the Company and Cal Water facilities contain financial covenants governing the Company and its subsidiaries' consolidated total capitalization ratio and interest coverage ratio. As of September 30, 2023, the Company and Cal Water are in compliance with all of the covenant requirements and are eligible to use the full amount of the undrawn portion of the Company and Cal Water facilities, as applicable. Borrowings on the Company facility as of each of September 30, 2023 and December 31, 2022 were $35.0 million. Borrowings on the Cal Water facility as of September 30, 2023 and December 31, 2022 were $80.0 million and $35.0 million, respectively. The average borrowing rate for borrowings on the Company and Cal Water facilities during the nine months ended September 30, 2023 was 5.96% compared to 2.18% for the same period last year.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company adjusts its effective tax rate each quarter to be consistent with the estimated annual effective tax rate. The Company also records the tax effect of unusual or infrequently occurring discrete items. The provision for income taxes is shown in the tables below: Three Months Ended September 30 2023 2022 Income tax expense $ 5,012 $ 6,243 Nine Months Ended September 30 2023 2022 Income tax expense $ 2,936 $ 7,137 Income tax expense decreased $1.2 million to $5.0 million in the third quarter of 2023 as compared to $6.2 million in the third quarter of 2022, primarily due to a decrease in the pre-tax income in the third quarter of 2023 as compared to the same period in 2022. Income tax expense decreased $4.2 million to $2.9 million for the first nine months of 2023 as compared to $7.1 million for the first nine months of 2022, primarily due to a decrease in the pre-tax income in the first nine months of 2023 as compared to 2022. The Company’s effective tax rate was 11.4% before discrete items as of September 30, 2023 and September 30, 2022. The Company had unrecognized tax benefits of approximately $14.8 million and $16.9 million as of September 30, 2023 and 2022, respectively. Included in the balance of unrecognized tax benefits as of September 30, 2023 and 2022, is $4.6 million and $4.2 million, respectively, of tax benefits that, if recognized, would result in an adjustment to the Company’s effective tax rate. The Company does not expect its unrecognized tax benefits to change significantly within the next 12 months.

Regulatory Assets and Liabiliti

Regulatory Assets and Liabilities	9 Months Ended
	Sep. 30, 2023
Regulated Operations [Abstract]
Regulatory Assets and Liabilities	Regulatory Assets and Liabilities Regulatory assets and liabilities were comprised of the following as of September 30, 2023 and December 31, 2022: Recovery Period September 30, 2023 December 31, 2022 Regulatory Assets Retiree group health Indefinite $ — $ 171 Property-related temporary differences (tax benefits flowed through to customers) Indefinite 143,546 143,546 Other accrued benefits Indefinite 25,762 24,946 Net WRAM and MCBA long-term accounts receivable Various 34,810 41,558 Asset retirement obligations, net Indefinite 26,930 24,548 Interim rates memorandum account (IRMA) long-term accounts receivable 1 - 2 years 3,407 3,682 Tank coating Various 18,910 16,395 Recoverable property losses Various 2,743 3,144 PCBA Various 3,661 19,091 General district balancing account receivable 1 year 389 377 Customer assistance program (CAP) and Rate support fund (RSF) accounts receivable 1 year 2,450 2,965 Other regulatory assets Various 3,022 3,197 Total Regulatory Assets $ 265,630 $ 283,620 Regulatory Liabilities Future tax benefits due to customers $ 131,218 $ 131,155 Pension and retiree group health 58,678 58,678 HCBA 2,771 14,318 PCBA 5,799 — CEBA 1,424 6,036 Net WRAM and MCBA long-term payable 2,065 172 Other components of net periodic benefit cost 7,975 2,475 RSF regulatory liability 1,269 — Other regulatory liabilities 1,465 845 Total Regulatory Liabilities $ 212,664 $ 213,679 Short-term regulatory assets and liabilities are excluded from the above table. The short-term regulatory assets were $52.9 million as of September 30, 2023 and $66.8 million as of December 31, 2022. The short-term regulatory assets as of September 30, 2023 primarily consist of net WRAM and MCBA and PCBA receivables. As of December 31, 2022, the short-term regulatory assets primarily consist of net WRAM and MCBA, IRMA, and PCBA receivables. The short-term portions of regulatory liabilities were $26.5 million as of September 30, 2023 and $12.2 million as of December 31, 2022. The short-term regulatory liabilities as of September 30, 2023 primarily consist of TCJA, HCBA and CEBA liabilities. As of December 31, 2022, the short-term regulatory liabilities primarily consist of TCJA liabilities.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments The Company has significant commitments to purchase water from water wholesalers. The Company also has operating and finance leases for water systems, offices, land easements, licenses, equipment, and other facilities. These commitments and leases are described in the Company's Annual Report on Form 10-K for the year ended December 31, 2022. On August 16, 2022, BVRT Utility Holding Company (BVRT), a majority owned subsidiary of Texas Water, entered into a long-term water supply agreement with the Guadalupe Blanco River Authority (GBRA) through its wholly owned subsidiary, Camino Real Utility (Camino Real). The Company has provided a limited guarantee to GBRA for the agreed upon obligations. GBRA is a water conservation and reclamation district established by the Texas Legislature that oversees water resources for 10 counties. Under the terms of the agreement with GBRA, Camino Real is contracted to receive up to 2,419 acre-feet of potable water annually. The GBRA agreement involves four off-takers, including Camino Real, and GBRA plans to extend a potable water pipeline from the City of Lockhart to the City of Mustang Ridge and surrounding areas. Camino Real is contracted to be the utility service provider in this area of the Austin metropolitan region and to provide potable water, recycled water, and wastewater services to portions of the City of Mustang Ridge and surrounding areas. In 2022, Camino Real committed $21.5 million for its share of the cost of the pipeline project and committed an additional $11.1 million for its share of the cost of the pipeline project in January of 2023. As of September 30, 2023, this committed cash has not been transferred to GBRA and is classified as part of restricted cash on the Condensed Consolidated Balance Sheets. The Company currently expects the committed cash to be transferred to GBRA in the first half of 2024. Contingencies Groundwater Contamination The Company has undertaken litigation against third parties to recover past and anticipated costs related to groundwater contamination in our service areas. The cost of litigation is expensed as incurred and any settlement is first offset against such costs. The CPUC’s general policy requires all proceeds from groundwater contamination litigation to be used first to pay transactional expenses, then to make customers whole for water treatment costs to comply with the CPUC’s water quality standards. The CPUC allows for a risk-based consideration of contamination proceeds which exceed the costs of the remediation described above and may result in some sharing of proceeds with shareholders, determined on a case by case basis. The CPUC has authorized various memorandum accounts that allow the Company to track significant litigation costs and to request recovery of these costs in future filings. Other Legal Matters From time to time, the Company is involved in various disputes and litigation matters that arise in the ordinary course of business. The status of each significant matter is reviewed and assessed for potential financial exposure. If the potential loss from any claim or legal proceeding is considered probable and the amount of the range of loss can be estimated, a liability is accrued for the estimated loss in accordance with the accounting standards for contingencies. Legal proceedings are subject to uncertainties, and the outcomes are difficult to predict. Because of such uncertainties, accruals are based on the best information available at the time. While the outcome of these disputes and litigation matters cannot be predicted with any certainty, management does not believe, when taking into account existing reserves, the ultimate resolution of these matters will materially affect the Company’s financial position, results of operations, or cash flows. As of September 30, 2023 and December 31, 2022, the Company recognized a liability of $5.6 million and $5.3 million, respectively, prior to insurance recoveries, for known legal matters primarily due to potable water leaks and other work-related legal matters. The cost of litigation is expensed as incurred and any settlement is first offset against such costs. Any settlement in excess of the cost to litigate is accounted for on a case by case basis, dependent on the nature of the settlement.

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets and Liabilities	Fair Value of Financial Assets and Liabilities The accounting guidance for fair value measurements and disclosures provides a single definition of fair value and requires certain disclosures about assets and liabilities measured at fair value. A hierarchical framework for disclosing the observability of the inputs utilized in measuring assets and liabilities at fair value is established by this guidance. The three levels in the hierarchy are as follows: Level 1 - Inputs to the valuation methodology are unadjusted quoted prices for identical assets or liabilities in active markets that the Company has the ability to access. Level 2 - Inputs to the valuation methodology include: • Quoted market prices for similar assets or liabilities in active markets; • Quoted prices for identical or similar assets or liabilities in inactive markets; • Inputs other than quoted prices that are observable for the asset or liability; and • Inputs that are derived principally from or corroborated by observable market data by correlation or other means. If the asset or liability has a specified (contractual) term, the level 2 input must be observable for substantially the full term of the asset or liability. Level 3 - Inputs to the valuation methodology are unobservable and significant to the fair value measurement. Specific valuation methods include the following: Cash, Accounts receivable, short-term borrowings, and accounts payable carrying amounts approximated the fair value because of the short-term maturity of the instruments. Long-term debt fair values were estimated using the published quoted market price of similar securities, if available, or the discounted cash flow analysis, based on the current rates available using a risk-free rate (a U.S. Treasury securities yield curve) plus a risk premium of 0.60%. September 30, 2023 Fair Value Cost Level 1 Level 2 Level 3 Total Long-term debt, including current maturities, net $ 1,053,669 $ — $ 895,182 $ — $ 895,182 December 31, 2022 Fair Value Cost Level 1 Level 2 Level 3 Total Long-term debt, including current maturities, net $ 1,055,797 $ — $ 977,227 $ — $ 977,227

Immaterial Restatement of Prior

Immaterial Restatement of Prior Period Financial Statements	9 Months Ended
	Sep. 30, 2023
Accounting Changes and Error Corrections [Abstract]
Immaterial Restatement of Prior Period Financial Statements	Immaterial Restatement of Prior Period Financial Statements Subsequent to the issuance of the Company's Consolidated Financial Statements for the year ended December 31, 2021, during the fourth quarter of 2022, the Company identified an immaterial error for a regulatory liability and corresponding decreases to operating revenue and deferred income taxes that were not recorded in 2019 associated with customer refunds. The error does not impact customer billings or cash refunded to customers. The Company corrected the error in the Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, through a restatement of the opening retained earnings balance for the year ended December 31, 2020. The Company believes the error is immaterial to the previously issued Financial Statements for prior periods. The corrections to the Company’s retained earnings and total equity as of September 30, 2022, June 30, 2022, and March 31, 2022, reported in note 4, were as follows: As of September 30, 2022 As Previously Reported Corrections As Corrected (In thousands) Retained earnings $ 561,907 $ (11,063) $ 550,844 Total equity $ 1,278,332 $ (11,063) $ 1,267,269 As of June 30, 2022 As Previously Reported Corrections As Corrected (In thousands) Retained earnings $ 519,625 $ (11,063) $ 508,562 Total equity $ 1,207,306 $ (11,063) $ 1,196,243 As of March 31, 2022 As Previously Reported Corrections As Corrected (In thousands) Retained earnings $ 513,593 $ (11,063) $ 502,530 Total equity $ 1,169,878 $ (11,063) $ 1,158,815

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ 34,438	$ 55,872	$ 21,783	$ 76,442

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The unaudited condensed consolidated interim financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) for interim financial information and in accordance with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X promulgated by the Securities and Exchange Commission (SEC) and therefore do not contain all of the information and footnotes required by GAAP and the SEC for annual financial statements. Interim financial information includes the Company's accounts and those of its wholly and non-wholly owned subsidiaries. The non-wholly owned subsidiary was consolidated using the voting interest model as the Company owns a majority of the non-wholly owned subsidiary's voting interests. The interim unaudited condensed consolidated financial statements should be read in conjunction with the Company’s consolidated financial statements included in its Annual Report on Form 10-K for the year ended December 31, 2022 as filed with the SEC on March 1, 2023. The preparation of the Company’s unaudited condensed consolidated interim financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the balance sheet dates and the reported amounts of revenues and expenses for the periods presented. These include, but are not limited to, estimates and assumptions used in determining the Company’s regulatory asset and liability balances based upon probability assessments of regulatory recovery, revenues earned but not yet billed, asset retirement obligations, allowance for credit losses, pension and other employee benefit plan liabilities, and income tax-related assets and liabilities. Actual results could materially differ from these estimates. In the opinion of management, the accompanying unaudited condensed consolidated interim financial statements reflect all adjustments, consisting of normal recurring transactions that are necessary to provide a fair presentation of the results for the periods covered. Due to the seasonal nature of the water business, the results for interim periods are not indicative of the results for a 12-month period. Revenue and income are generally higher in the warm, dry summer months when water usage and sales are greater. Revenue and income are generally lower in the winter months when cooler temperatures and rainfall curtail water usage and sales.
Revenue	Revenue from contracts with customers The Company principally generates operating revenue from contracts with customers by providing regulated water and wastewater services at tariff-rates authorized by the Commissions in the states in which they operate and non-regulated water and wastewater services at rates authorized by contracts with government agencies. Revenue from contracts with customers reflects amounts billed for the volume of consumption at authorized per unit rates, for a service charge, and for other authorized charges. The Company satisfies its performance obligation to provide water and wastewater services over time as services are rendered. The Company applies the invoice practical expedient and recognizes revenue from contracts with customers in the amount for which the Company has a right to invoice. The Company has a right to invoice for the volume of consumption, for the service charge, and for other authorized charges. The measurement of sales to customers is generally based on the reading of their meters, which occurs on a systematic basis throughout the month. At the end of each month, the Company estimates consumption since the date of the last meter reading and the corresponding unbilled revenue is recognized. The estimate is based upon the number of unbilled days that month and the average daily customer billing rate from the previous month (which fluctuates based upon customer usage). Contract terms are generally short-term and at will by customers and, as a result, no separate financing component is recognized for the Company's collections from customers, which generally require payment within 30 days of billing. The Company applies judgment, based principally on historical payment experience, in estimating its customers’ ability to pay. Certain customers are not billed for volumetric consumption, but are instead billed a flat rate at the beginning of each monthly service period. The amount billed is initially deferred and subsequently recognized over the monthly service period, as the performance obligation is satisfied. The deferred revenue balance or contract liability, which is included in "accrued expenses and other liabilities" on the unaudited condensed consolidated balance sheets, is inconsequential. In the following tables, revenue from contracts with customers is disaggregated by class of customers for the three and nine months ended September 30, 2023 and 2022: Three Months Ended September 30 2023 2022 Residential $ 150,031 $ 140,585 Business 47,707 44,031 Multiple residential 18,778 17,333 Industrial 8,165 8,086 Public authorities 14,522 13,441 Other (a) 14,134 14,792 Total revenue from contracts with customers $ 253,337 $ 238,268 Nine Months Ended September 30 2023 2022 Residential $ 342,806 $ 348,965 Business 117,527 115,472 Multiple residential 50,280 48,343 Industrial 19,672 20,174 Public authorities 29,938 31,310 Other (a) 32,545 31,596 Total revenue from contracts with customers $ 592,768 $ 595,860 (a) Other includes accrued unbilled revenue. Regulatory balancing account revenue Regulatory balancing account revenue is revenue related to revenue mechanisms authorized in California by the California Public Utilities Commission (CPUC), which allow the Company to recognize revenue when it is objectively determinable, probable of recovery and expected to be collected within 24 months following the end of the accounting period, and are not considered contracts with customers and are not included in the total revenue from contracts with customers in the table above. To the extent that revenue is estimated to be collectible beyond 24 months, recognition is deferred. Due to a delay in resolution of the most recent Cal Water General Rate Case (GRC) filing (2021 GRC Filing), the Company did not recognize a benefit from any regulatory revenue mechanisms in the first nine months of 2023. For 2022, the Company's authorized regulatory revenue mechanisms included the Water Revenue Adjustment Mechanism (WRAM). The WRAM decoupled revenue from the volume of the sales and allowed the Company to recognize the adopted level of volumetric revenues. The variance between adopted volumetric revenues and actual billed volumetric revenues for metered accounts was recorded as regulatory balancing account revenue. The WRAM concluded on December 31, 2022. Regulatory balancing accounts also includes revenue that is recognized for balancing accounts when it is probable that future recovery of previously incurred costs or future refunds that are to be credited to customers will occur through the ratemaking process. These mechanisms, such as the Modified Cost Balancing Account (MCBA), Conservation Expense Balancing Account (CEBA), Pension Cost Balancing Account (PCBA), and Health Cost Balancing Account (HCBA), generally provide for recovery of the adopted levels of expenses for purchased water, purchased power, pump taxes, water conservation program costs, pension, and health care. Variances between adopted and actual costs were recorded as regulatory balancing account revenue in 2022. In 2023, in connection with the CPUC's decision to discontinue the use of the WRAM, the variances for CEBA, HCBA, and PCBA are recorded against the originating expense. The MCBA concluded on December 31, 2022.
Non-regulated Revenue	Non-regulated Revenue The following tables disaggregate the Company’s non-regulated revenue by source for the three and nine months ended September 30, 2023 and 2022: Three Months Ended September 30 2023 2022 Operating and maintenance revenue $ 2,918 $ 3,184 Other non-regulated revenue 972 720 Non-regulated revenue from contracts with customers 3,890 3,904 Lease revenue 645 669 Total non-regulated revenue $ 4,535 $ 4,573 Nine Months Ended September 30 2023 2022 Operating and maintenance revenue $ 9,229 $ 9,822 Other non-regulated revenue 2,553 4,951 Non-regulated revenue from contracts with customers 11,782 14,773 Lease revenue 1,861 1,999 Total non-regulated revenue $ 13,643 $ 16,772 Operating and maintenance services are provided for non-regulated water and wastewater systems owned by private companies and municipalities. The Company negotiates formal agreements with the customers, under which they provide operating, maintenance and customer billing services related to the customers’ water system. The formal agreements outline the fee schedule for the services provided. The agreements typically call for a fee-per-service or a flat-rate amount per month. The Company satisfies its performance obligation of providing operating and maintenance services over time as services are rendered; as a result, the Company employs the invoice practical expedient and recognizes revenue in the amount that it has the right to invoice. Contract terms are generally short-term and, as a result, no separate financing component is recognized for its collections from customers, which generally require payment within 30 days of billing. Other non-regulated revenue primarily relates to services for the design and installation of water mains and other water infrastructure for customers outside the regulated service areas and insurance program administration. During the first nine months of 2022, the Company recorded a gain of $2.7 million related to company owned life insurance.
Lease revenue	Lease revenue is not considered revenue from contracts with customers and is recognized following operating lease standards. The Company is the lessor in operating lease agreements with telecommunications companies under which cellular phone antennas are placed on the Company's property.
Allowance for credit losses	Allowance for credit losses The Company measures expected credit losses for Customer Receivables, Other Receivables, and Unbilled Revenue on an aggregated level. These receivables are generally trade receivables due in one year or less or expected to be billed and collected in one year or less. The expected credit losses for Other Receivables and Unbilled Revenue are inconsequential. Customer receivables include receivables for water and wastewater services provided to residential customers, business, industrial, public authorities, and other customers. The expected credit losses for business, industrial, public authorities, and other customers are inconsequential. The overall risks related to the Company’s receivables are low as water and wastewater services are seen as essential services. The estimate for the allowance for credit losses is based on a historical loss ratio, in conjunction with a qualitative assessment of elements that impact the collectability of receivables to determine if the allowance for credit losses should be further adjusted. Management's assessment contemplates available current information such as changes in economic factors, regulatory matters, industry trends, payment options and programs available to customers, and the methods that the Company is able to utilize to ensure payment. The Company reviews its allowance for credit losses utilizing a quantitative assessment, which includes a trend analysis of customer billings and collections, agings by customer class, and unemployment rates. The Company also utilizes a qualitative assessment, which considers the future collectability on customer outstanding balances, management's estimate of the cash recovery, and a general assessment of the economic conditions in the locations the Company serves. Based on these assessments, the Company adjusts its allowance for credit losses.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Disaggregation of Revenue	The following tables disaggregate the Company’s operating revenue by source for the three and nine months ended September 30, 2023 and 2022: Three Months Ended September 30 2023 2022 Revenue from contracts with customers $ 253,337 $ 238,268 Regulatory balancing account revenue 1,639 28,039 Total operating revenue $ 254,976 $ 266,307 Nine Months Ended September 30 2023 2022 Revenue from contracts with customers $ 592,768 $ 595,860 Regulatory balancing account revenue (12,648) 49,634 Total operating revenue $ 580,120 $ 645,494 In the following tables, revenue from contracts with customers is disaggregated by class of customers for the three and nine months ended September 30, 2023 and 2022: Three Months Ended September 30 2023 2022 Residential $ 150,031 $ 140,585 Business 47,707 44,031 Multiple residential 18,778 17,333 Industrial 8,165 8,086 Public authorities 14,522 13,441 Other (a) 14,134 14,792 Total revenue from contracts with customers $ 253,337 $ 238,268 Nine Months Ended September 30 2023 2022 Residential $ 342,806 $ 348,965 Business 117,527 115,472 Multiple residential 50,280 48,343 Industrial 19,672 20,174 Public authorities 29,938 31,310 Other (a) 32,545 31,596 Total revenue from contracts with customers $ 592,768 $ 595,860 (a) Other includes accrued unbilled revenue. The following tables disaggregate the Company’s non-regulated revenue by source for the three and nine months ended September 30, 2023 and 2022: Three Months Ended September 30 2023 2022 Operating and maintenance revenue $ 2,918 $ 3,184 Other non-regulated revenue 972 720 Non-regulated revenue from contracts with customers 3,890 3,904 Lease revenue 645 669 Total non-regulated revenue $ 4,535 $ 4,573 Nine Months Ended September 30 2023 2022 Operating and maintenance revenue $ 9,229 $ 9,822 Other non-regulated revenue 2,553 4,951 Non-regulated revenue from contracts with customers 11,782 14,773 Lease revenue 1,861 1,999 Total non-regulated revenue $ 13,643 $ 16,772
Schedule of Allowance for Credit Losses	The following table presents the activity in the allowance for credit losses for the 9-month period ended September 30, 2023 and 12-month period ended December 31, 2022: Allowance for credit losses September 30, 2023 December 31, 2022 Beginning balance $ 5,629 $ 3,743 Provision for credit loss expense 3,274 5,887 Write-offs (4,527) (4,380) Recoveries 413 379 Total ending allowance balance $ 4,789 $ 5,629
Schedule of Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the Condensed Consolidated Balance Sheets that sum to the total of the same such amounts shown on the Condensed Consolidated Statements of Cash Flows (see Note 10 for further details on restricted cash): September 30, 2023 December 31, 2022 Cash and cash equivalents $ 34,735 $ 62,100 Restricted cash 34,315 22,925 Total cash, cash equivalents, and restricted cash shown in the statements of cash flows $ 69,050 $ 85,025

Stock-based Compensation (Table

Stock-based Compensation (Tables)	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of Restricted Stock and Restricted Stock Unit Activity	A summary of the status of outstanding RSAs as of September 30, 2023 is presented below: Number of RSA Shares Weighted-Average Grant-Date Fair Value RSAs at January 1, 2023 52,066 $ 55.77 Granted 43,834 55.38 Vested (37,210) 55.76 Forfeited (2,025) 55.59 RSAs at September 30, 2023 56,665 $ 55.50 A summary of the status of outstanding RSUs as of September 30, 2023 is presented below: Number of RSU Shares Weighted-Average Grant-Date Fair Value RSUs at January 1, 2023 92,625 $ 54.06 Granted 43,633 55.48 Performance criteria adjustment 14,822 56.84 Vested (40,589) 56.84 Forfeited (14,309) 54.25 RSUs at September 30, 2023 96,182 $ 55.40

Equity (Tables)

Equity (Tables)	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Schedule of Changes in Total Common Stockholders' Equity	The Company’s changes in total equity for the three and nine months ended September 30, 2023 and 2022 were as follows: Nine months ended September 30, 2023 Common Stock Additional Retained Noncontrolling Interests Total Equity Shares Amount (In thousands) Balance at January 1, 2023 55,598 $ 556 $ 760,336 $ 556,698 $ 4,804 $ 1,322,394 Net loss — — — (22,211) (123) (22,334) Issuance of common stock 420 4 18,922 — — 18,926 Repurchase of common stock (27) — (1,542) — — (1,542) Dividends paid on common stock ($0.2600 per share) — — — (14,456) — (14,456) Investment in business with noncontrolling interest — — (111) — 111 — Balance at March 31, 2023 55,991 560 777,605 520,031 4,792 1,302,988 Net income (loss) — — — 9,556 (109) 9,447 Issuance of common stock 1,713 17 96,482 — — 96,499 Repurchase of common stock (2) — (108) — — (108) Dividends paid on common stock ($0.2600 per share) — — — (14,571) — (14,571) Investment in business with noncontrolling interest — — (56) — 56 — Distribution to noncontrolling interest — — — — (288) (288) Balance at June 30, 2023 57,702 577 873,923 515,016 4,451 1,393,967 Net income (loss) — — — 34,438 (113) 34,325 Issuance of common stock 11 — 1,796 — — 1,796 Repurchase of common stock (2) — (90) — — (90) Dividends paid on common stock ($0.2600 per share) — — — (15,003) — (15,003) Investment in business with noncontrolling interest — — 11 — (11) — Balance at September 30, 2023 57,711 $ 577 $ 875,640 $ 534,451 $ 4,327 $ 1,414,995 Nine months ended September 30, 2022 Common Stock Additional Retained Noncontrolling Interests Total Equity Shares Amount (In thousands) Balance at January 1, 2022 53,716 $ 537 $ 651,121 $ 514,873 $ 5,386 $ 1,171,917 Net income (loss) — — — 1,086 (192) 894 Issuance of common stock 85 1 1,106 — — 1,107 Repurchase of common stock (28) — (1,674) — — (1,674) Dividends paid on common stock ($0.2500 per share) — — — (13,429) — (13,429) Investment in business with noncontrolling interest — — (54) — 54 — Balance at March 31, 2022 53,773 538 650,499 502,530 5,248 1,158,815 Net income (loss) — — — 19,484 (269) 19,215 Issuance of common stock 585 6 32,118 — — 32,124 Repurchase of common stock (2) — (111) — — (111) Dividends paid on common stock ($0.2500 per share) — — — (13,452) — (13,452) Investment in business with noncontrolling interest — — (153) — 153 — Distribution to noncontrolling interest — — — — (348) (348) Balance at June 30, 2022 54,356 544 682,353 508,562 4,784 1,196,243 Net income (loss) — — — 55,872 (189) 55,683 Issuance of common stock 470 4 29,034 — — 29,038 Repurchase of common stock (2) — (105) — — (105) Dividends paid on common stock ($0.2500 per share) — — — (13,590) — (13,590) Investment in business with noncontrolling interest — — (278) — 278 — Balance at September 30, 2022 54,824 $ 548 $ 711,004 $ 550,844 $ 4,873 $ 1,267,269

Earnings Per Share of Common _2

Earnings Per Share of Common Stock (Tables)	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Schedule basic and Diluted Earnings Per Share	The computations of basic and diluted earnings per share of common stock are noted in the tables below. Basic earnings per share of common stock is computed by dividing the net income attributable to California Water Service Group by the weighted average number of common shares outstanding during the period. RSAs are included in the weighted average common shares outstanding because the shares have all the same voting and dividend rights as issued and unrestricted common stock. Three Months Ended September 30 2023 2022 (In thousands, except per share data) Net income $ 34,325 $ 55,683 Net loss attributable to noncontrolling interests $ (113) $ (189) Net income attributable to California Water Service Group $ 34,438 $ 55,872 Weighted average common shares outstanding, basic 57,704 54,007 Weighted average common shares outstanding, dilutive 57,740 54,042 Earnings per share of common stock - basic $ 0.60 $ 1.03 Earnings per share of common stock - diluted $ 0.60 $ 1.03 Nine Months Ended September 30 2023 2022 (In thousands, except per share data) Net income $ 21,438 $ 75,792 Net loss attributable to noncontrolling interests $ (345) $ (650) Net income attributable to California Water Service Group $ 21,783 $ 76,442 Weighted average common shares outstanding, basic 56,695 54,063 Weighted average common shares outstanding, dilutive 56,731 54,104 Earnings per share of common stock - basic $ 0.38 $ 1.41 Earnings per share of common stock - diluted $ 0.38 $ 1.41

Pension Plan and Other Postre_2

Pension Plan and Other Postretirement Benefits (Tables)	9 Months Ended
	Sep. 30, 2023
Retirement Benefits [Abstract]
Schedule of components of net periodic benefit costs for the pension plans and other postretirement benefits	The following tables list components of net periodic benefit costs for the pension plans and other postretirement benefits. The data listed under “pension plan” includes the qualified pension plan and the non-qualified supplemental executive retirement plan. The data listed under “other benefits” is for all other postretirement benefits. Three Months Ended September 30 Pension Plan Other Benefits 2023 2022 2023 2022 Service cost $ 6,046 $ 9,235 $ 1,126 $ 1,683 Interest cost 8,746 6,329 1,297 1,008 Expected return on plan assets (13,421) (11,307) (2,636) (2,482) Amortization of prior service cost 131 242 39 39 Recognized net actuarial (gain) loss (637) 999 (581) (228) Net periodic benefit cost (credit) $ 865 $ 5,498 $ (755) $ 20 Nine Months Ended September 30 Pension Plan Other Benefits 2023 2022 2023 2022 Service cost $ 18,137 $ 27,704 $ 3,379 $ 5,048 Interest cost 26,238 18,986 3,892 3,024 Expected return on plan assets (40,263) (33,920) (7,907) (7,445) Amortization of prior service cost 394 727 116 117 Recognized net actuarial (gain) loss (1,911) 2,997 (1,744) (685) Net periodic benefit cost (credit) $ 2,595 $ 16,494 $ (2,264) $ 59

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The provision for income taxes is shown in the tables below: Three Months Ended September 30 2023 2022 Income tax expense $ 5,012 $ 6,243 Nine Months Ended September 30 2023 2022 Income tax expense $ 2,936 $ 7,137

Regulatory Assets and Liabili_2

Regulatory Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2023
Regulated Operations [Abstract]
Schedule of Regulatory Assets and Liabilities	Regulatory assets and liabilities were comprised of the following as of September 30, 2023 and December 31, 2022: Recovery Period September 30, 2023 December 31, 2022 Regulatory Assets Retiree group health Indefinite $ — $ 171 Property-related temporary differences (tax benefits flowed through to customers) Indefinite 143,546 143,546 Other accrued benefits Indefinite 25,762 24,946 Net WRAM and MCBA long-term accounts receivable Various 34,810 41,558 Asset retirement obligations, net Indefinite 26,930 24,548 Interim rates memorandum account (IRMA) long-term accounts receivable 1 - 2 years 3,407 3,682 Tank coating Various 18,910 16,395 Recoverable property losses Various 2,743 3,144 PCBA Various 3,661 19,091 General district balancing account receivable 1 year 389 377 Customer assistance program (CAP) and Rate support fund (RSF) accounts receivable 1 year 2,450 2,965 Other regulatory assets Various 3,022 3,197 Total Regulatory Assets $ 265,630 $ 283,620 Regulatory Liabilities Future tax benefits due to customers $ 131,218 $ 131,155 Pension and retiree group health 58,678 58,678 HCBA 2,771 14,318 PCBA 5,799 — CEBA 1,424 6,036 Net WRAM and MCBA long-term payable 2,065 172 Other components of net periodic benefit cost 7,975 2,475 RSF regulatory liability 1,269 — Other regulatory liabilities 1,465 845 Total Regulatory Liabilities $ 212,664 $ 213,679

Fair Value of Financial Asset_2

Fair Value of Financial Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Long-term Debt	September 30, 2023 Fair Value Cost Level 1 Level 2 Level 3 Total Long-term debt, including current maturities, net $ 1,053,669 $ — $ 895,182 $ — $ 895,182 December 31, 2022 Fair Value Cost Level 1 Level 2 Level 3 Total Long-term debt, including current maturities, net $ 1,055,797 $ — $ 977,227 $ — $ 977,227

Immaterial Restatement of Pri_2

Immaterial Restatement of Prior Period Financial Statements (Tables)	9 Months Ended
	Sep. 30, 2023
Accounting Changes and Error Corrections [Abstract]
Schedule of Error Corrections and Prior Period Adjustments	The corrections to the Company’s retained earnings and total equity as of September 30, 2022, June 30, 2022, and March 31, 2022, reported in note 4, were as follows: As of September 30, 2022 As Previously Reported Corrections As Corrected (In thousands) Retained earnings $ 561,907 $ (11,063) $ 550,844 Total equity $ 1,278,332 $ (11,063) $ 1,267,269 As of June 30, 2022 As Previously Reported Corrections As Corrected (In thousands) Retained earnings $ 519,625 $ (11,063) $ 508,562 Total equity $ 1,207,306 $ (11,063) $ 1,196,243 As of March 31, 2022 As Previously Reported Corrections As Corrected (In thousands) Retained earnings $ 513,593 $ (11,063) $ 502,530 Total equity $ 1,169,878 $ (11,063) $ 1,158,815

Organization and Operations a_2

Organization and Operations and Basis of Presentation (Details)	9 Months Ended
	Sep. 30, 2023 segment
Noncontrolling Interest [Line Items]
Number of reportable segments	1
BVRT Water Company
Noncontrolling Interest [Line Items]
Noncontrolling interest	5.50%

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 253,337	$ 238,268	$ 592,768	$ 595,860
Regulatory balancing account revenue	1,639	28,039	(12,648)	49,634
Operating revenue	254,976	266,307	580,120	645,494
Total non-regulated revenue	4,535	4,573	13,643	16,772
Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	150,031	140,585	342,806	348,965
Business
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	47,707	44,031	117,527	115,472
Multiple residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	18,778	17,333	50,280	48,343
Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8,165	8,086	19,672	20,174
Public authorities
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	14,522	13,441	29,938	31,310
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	14,134	14,792	32,545	31,596
Operating and maintenance revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,918	3,184	9,229	9,822
Other non-regulated revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	972	720	2,553	4,951
Non-regulated revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,890	3,904	11,782	14,773
Lease revenue	645	669	1,861	1,999
Total non-regulated revenue	$ 4,535	$ 4,573	$ 13,643	16,772
Insurance Program
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers				$ 2,700

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 5,629	$ 3,743
Provision for credit loss expense	3,274	5,887
Write-offs	(4,527)	(4,380)
Recoveries	413	379
Total ending allowance balance	$ 4,789	$ 5,629

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Cash and cash equivalents	$ 34,735	$ 62,100
Restricted cash	34,315	22,925
Total cash, cash equivalents, and restricted cash shown in the statements of cash flows	$ 69,050	$ 85,025	$ 113,442	$ 80,653

Stock-based Compensation - Narr

Stock-based Compensation - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Stock-based Compensation
Shares authorized to be issued under the plan (in shares)	2,000,000		2,000,000
Recorded compensation costs for the RSAs and RSUs	$ 1.2	$ 1.6	$ 2.7	$ 3.5
RSAs
Stock-based Compensation
Period for recognition			1 year 8 months 12 days
Unrecognized compensation cost	2.3		$ 2.3
Performance-Based Restricted Stock Unit Awards (RSUs)
Stock-based Compensation
Period for recognition			2 years
Unrecognized compensation cost	$ 2.9		$ 2.9
Performance period			3 years
Performance-Based Restricted Stock Unit Awards (RSUs) | Minimum
Stock-based Compensation
Options vested on anniversary date			0%
Performance-Based Restricted Stock Unit Awards (RSUs) | Maximum
Stock-based Compensation
Options vested on anniversary date			200%
Officer | RSAs
Stock-based Compensation
Vesting period			36 months
Period for recognition			36 months
Director | RSAs
Stock-based Compensation
Vesting period			12 months
Period for recognition			12 months

Stock-based Compensation - RSAs

Stock-based Compensation - RSAs & Performance-Based RSUs (Details)	9 Months Ended
	Sep. 30, 2023 $ / shares shares
RSAs
Number of shares
Beginning balance (in shares) | shares	52,066
Granted (in shares) | shares	43,834
Vested (in shares) | shares	(37,210)
Forfeited (in shares) | shares	(2,025)
Ending balance (in shares) | shares	56,665
Weighted average price at grant
Beginning balance (in dollars per share) | $ / shares	$ 55.77
Granted (in dollars per share) | $ / shares	55.38
Vested (in dollars per share) | $ / shares	55.76
Forfeited (in dollars per share) | $ / shares	55.59
Ending balance (in dollars per share) | $ / shares	$ 55.50
RSUs
Number of shares
Beginning balance (in shares) | shares	92,625
Granted (in shares) | shares	43,633
Performance criteria adjustment (in shares) | shares	14,822
Vested (in shares) | shares	(40,589)
Forfeited (in shares) | shares	(14,309)
Ending balance (in shares) | shares	96,182
Weighted average price at grant
Beginning balance (in dollars per share) | $ / shares	$ 54.06
Granted (in dollars per share) | $ / shares	55.48
Performance criteria adjustment (in dollars per share) | $ / shares	56.84
Vested (in dollars per share) | $ / shares	56.84
Forfeited (in dollars per share) | $ / shares	54.25
Ending balance (in dollars per share) | $ / shares	$ 55.40

Equity - Narrative (Details)

Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended	9 Months Ended
	Apr. 29, 2022	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Jul. 26, 2022	Jul. 25, 2022
Equity [Abstract]
Maximum consideration on transaction	$ 350
Sale of stock, agreement term	3 years
Sale of stock, number of shares issued in transaction (in shares)		461,034	2,025,891	1,035,668
Issuance of common stock, net		$ 26.9	$ 112.7	$ 57.1
Payments for commissions		$ 0.3	$ 1.1	$ 0.6
Common stock, shares authorized (in shares)			136,000,000		136,000,000	136,000,000	68,000,000
Common stock, par value (in dollars per share)			$ 0.01		$ 0.01	$ 0.01

Equity - Changes in Equity (Det

Equity - Changes in Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period (in shares)			55,598,000				55,598,000
Balance at beginning of period	$ 1,393,967	$ 1,302,988	$ 1,322,394	$ 1,196,243	$ 1,158,815	$ 1,171,917	$ 1,322,394	$ 1,171,917
Net income (loss)	34,325	9,447	(22,334)	55,683	19,215	894	$ 21,438	75,792
Issuance of common stock	1,796	96,499	18,926	29,038	32,124	1,107
Repurchase of common stock	(90)	(108)	(1,542)	(105)	(111)	(1,674)
Dividends paid on common stock	(15,003)	(14,571)	(14,456)	(13,590)	(13,452)	(13,429)
Investment in business with noncontrolling interest	$ 0	0	0	0	0	0
Distribution to noncontrolling interest		(288)			(348)
Balance at end of period (in shares)	57,711,000						57,711,000
Balance at end of period	$ 1,414,995	$ 1,393,967	$ 1,302,988	$ 1,267,269	$ 1,196,243	$ 1,158,815	$ 1,414,995	$ 1,267,269
Dividends paid on common stock (in dollars per share)	$ 0.2600	$ 0.2600	$ 0.2600	$ 0.2500	$ 0.2500	$ 0.2500
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period (in shares)	57,702,000	55,991,000	55,598,000	54,356,000	53,773,000	53,716,000	55,598,000	53,716,000
Balance at beginning of period	$ 577	$ 560	$ 556	$ 544	$ 538	$ 537	$ 556	$ 537
Issuance of common stock (in shares)	11,000	1,713,000	420,000	470,000	585,000	85,000
Issuance of common stock		$ 17	$ 4	$ 4	$ 6	$ 1
Repurchase of common stock (in shares)	(2,000)	(2,000)	(27,000)	(2,000)	(2,000)	(28,000)
Balance at end of period (in shares)	57,711,000	57,702,000	55,991,000	54,824,000	54,356,000	53,773,000	57,711,000	54,824,000
Balance at end of period	$ 577	$ 577	$ 560	$ 548	$ 544	$ 538	$ 577	$ 548
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	873,923	777,605	760,336	682,353	650,499	651,121	760,336	651,121
Issuance of common stock	1,796	96,482	18,922	29,034	32,118	1,106
Repurchase of common stock	(90)	(108)	(1,542)	(105)	(111)	(1,674)
Investment in business with noncontrolling interest	11	(56)	(111)	(278)	(153)	(54)
Balance at end of period	875,640	873,923	777,605	711,004	682,353	650,499	875,640	711,004
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	515,016	520,031	556,698	508,562	502,530	514,873	556,698	514,873
Net income (loss)	34,438	9,556	(22,211)	55,872	19,484	1,086
Dividends paid on common stock	(15,003)	(14,571)	(14,456)	(13,590)	(13,452)	(13,429)
Balance at end of period	534,451	515,016	520,031	550,844	508,562	502,530	534,451	550,844
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	4,451	4,792	4,804	4,784	5,248	5,386	4,804	5,386
Net income (loss)	(113)	(109)	(123)	(189)	(269)	(192)
Investment in business with noncontrolling interest	(11)	56	111	278	153	54
Distribution to noncontrolling interest		(288)			(348)
Balance at end of period	$ 4,327	$ 4,451	$ 4,792	$ 4,873	$ 4,784	$ 5,248	$ 4,327	$ 4,873

Earnings Per Share of Common _3

Earnings Per Share of Common Stock (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Earnings Per Share [Abstract]
Net income	$ 34,325	$ 9,447	$ (22,334)	$ 55,683	$ 19,215	$ 894	$ 21,438	$ 75,792
Net loss attributable to noncontrolling interests	(113)			(189)			(345)	(650)
Net income attributable to California Water Service Group	$ 34,438			$ 55,872			$ 21,783	$ 76,442
Weighted average common shares outstanding, basic (in shares)	57,704			54,007			56,695	54,063
Weighted average common shares outstanding, dilutive (in shares)	57,740			54,042			56,731	54,104
Earnings per share of common stock - basic (in dollars per share)	$ 0.60			$ 1.03			$ 0.38	$ 1.41
Earnings per share of common stock - diluted (in dollars per share)	$ 0.60			$ 1.03			$ 0.38	$ 1.41

Pension Plan and Other Postre_3

Pension Plan and Other Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pension Plan
Pension Plan and Other Postretirement Benefits
Employer cash contributions			$ 2,900	$ 12,400
Estimated cash contributions in the current fiscal year	$ 2,900		2,900
Components of the pension plans and other postretirement benefits
Service cost	6,046	$ 9,235	18,137	27,704
Interest cost	8,746	6,329	26,238	18,986
Expected return on plan assets	(13,421)	(11,307)	(40,263)	(33,920)
Amortization of prior service cost	131	242	394	727
Recognized net actuarial (gain) loss	(637)	999	(1,911)	2,997
Net periodic benefit cost (credit)	865	5,498	2,595	16,494
Other Benefits
Pension Plan and Other Postretirement Benefits
Employer cash contributions			200	500
Estimated cash contributions in the current fiscal year	200		200
Components of the pension plans and other postretirement benefits
Service cost	1,126	1,683	3,379	5,048
Interest cost	1,297	1,008	3,892	3,024
Expected return on plan assets	(2,636)	(2,482)	(7,907)	(7,445)
Amortization of prior service cost	39	39	116	117
Recognized net actuarial (gain) loss	(581)	(228)	(1,744)	(685)
Net periodic benefit cost (credit)	$ (755)	$ 20	$ (2,264)	$ 59

Short-term and Long-term Borr_2

Short-term and Long-term Borrowings (Details) - USD ($)			9 Months Ended
	Mar. 31, 2023	Mar. 29, 2019	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Cal Water
Debt Instrument [Line Items]
Outstanding borrowings			$ 80,000,000		$ 35,000,000
Parent Company
Debt Instrument [Line Items]
Outstanding borrowings			$ 35,000,000		$ 35,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 600,000,000
Debt instrument, term	5 years
Average borrowing rate			5.96%	2.18%
Revolving Credit Facility | Base Rate | Minimum
Debt Instrument [Line Items]
Interest rate		0%
Revolving Credit Facility | Base Rate | Maximum
Debt Instrument [Line Items]
Interest rate		0.25%
Revolving Credit Facility | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Minimum
Debt Instrument [Line Items]
Interest rate		0.80%
Revolving Credit Facility | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Maximum
Debt Instrument [Line Items]
Interest rate		1.25%
Revolving Credit Facility | Cal Water
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 400,000,000
Incremental expansion of borrowing capacity	150,000,000
Revolving Credit Facility | Parent Company
Debt Instrument [Line Items]
Maximum borrowing capacity	200,000,000
Incremental expansion of borrowing capacity	$ 50,000,000

Income Taxes - Provision for In

Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Income tax expense	$ 5,012	$ 6,243	$ 2,936	$ 7,137

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Decrease in income tax expense	$ 1,200		$ 4,200
Income tax expense (benefit)	5,012	$ 6,243	$ 2,936	$ 7,137
Effective tax rate estimate			11.40%	11.40%
Unrecognized tax benefits	14,800	16,900	$ 14,800	$ 16,900
Tax benefits that, if recognized, would affect the effective tax rate	$ 4,600	$ 4,200	$ 4,600	$ 4,200

Regulatory Assets and Liabili_3

Regulatory Assets and Liabilities - Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	$ 265,630	$ 283,620
Total Regulatory Liabilities	212,664	213,679
Future tax benefits due to customers
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	131,218	131,155
Pension and retiree group health
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	58,678	58,678
HCBA
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	2,771	14,318
PCBA
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	5,799	0
CEBA
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	1,424	6,036
Net WRAM and MCBA long-term payable
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	2,065	172
Other components of net periodic benefit cost
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	7,975	2,475
RSF regulatory liability
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	1,269	0
Other regulatory liabilities
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	1,465	845
Retiree group health
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	0	171
Future tax benefits due to customers
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	143,546	143,546
Other accrued benefits
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	25,762	24,946
Net WRAM and MCBA long-term accounts receivable
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	34,810	41,558
Asset retirement obligations, net
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	26,930	24,548
Interim rates memorandum account (IRMA) long-term accounts receivable
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	3,407	3,682
Tank coating
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	18,910	16,395
Recoverable property losses
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	2,743	3,144
PCBA
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	$ 3,661	19,091
General district balancing account receivable
Regulatory Assets and Liabilities [Line Items]
Recovery Period	1 year
Total Regulatory Assets	$ 389	377
Customer assistance program (CAP) and Rate support fund (RSF) accounts receivable
Regulatory Assets and Liabilities [Line Items]
Recovery Period	1 year
Total Regulatory Assets	$ 2,450	2,965
Other regulatory assets
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	$ 3,022	$ 3,197
Minimum | Interim rates memorandum account (IRMA) long-term accounts receivable
Regulatory Assets and Liabilities [Line Items]
Recovery Period	1 year
Maximum | Interim rates memorandum account (IRMA) long-term accounts receivable
Regulatory Assets and Liabilities [Line Items]
Recovery Period	2 years

Regulatory Assets and Liabili_4

Regulatory Assets and Liabilities - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Regulated Operations [Abstract]
Short-term portion of the regulatory assets	$ 52,918	$ 66,826
Short-term portion of the regulatory liabilities	$ 26,458	$ 12,240

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2023	Dec. 31, 2022	Sep. 30, 2023
Lessee, Lease, Description [Line Items]
Contingency loss recognized liability		$ 5.3	$ 5.6
Camino Real | Supply Commitment
Lessee, Lease, Description [Line Items]
Payments for other commitments	$ 11.1	$ 21.5

Fair Value of Financial Asset_3

Fair Value of Financial Assets and Liabilities - Narrative (Details)	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Risk premium (as a percent)	0.60%

Fair Value of Financial Asset_4

Fair Value of Financial Assets and Liabilities - Schedule of Long Term Debt at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Cost
Fair Value of Financial Assets and Liabilities
Long-term debt, including current maturities, net	$ 1,053,669	$ 1,055,797
Fair Value
Fair Value of Financial Assets and Liabilities
Long-term debt, including current maturities, net	895,182	977,227
Fair Value | Level 1
Fair Value of Financial Assets and Liabilities
Long-term debt, including current maturities, net	0	0
Fair Value | Level 2
Fair Value of Financial Assets and Liabilities
Long-term debt, including current maturities, net	895,182	977,227
Fair Value | Level 3
Fair Value of Financial Assets and Liabilities
Long-term debt, including current maturities, net	$ 0	$ 0

Immaterial Restatement of Pri_3

Immaterial Restatement of Prior Period Financial Statements (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Retained earnings	$ 534,451			$ 556,698	$ 550,844	$ 508,562	$ 502,530
Total equity	$ 1,414,995	$ 1,393,967	$ 1,302,988	$ 1,322,394	1,267,269	1,196,243	1,158,815	$ 1,171,917
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Retained earnings					561,907	519,625	513,593
Total equity					1,278,332	1,207,306	1,169,878
Corrections
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Retained earnings					(11,063)	(11,063)	(11,063)
Total equity					$ (11,063)	$ (11,063)	$ (11,063)