Mueller Water Products (MWA) 10-Q 3 May 22 2022 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Mar. 31, 2022	Apr. 30, 2022
Document And Entity Information [Abstract]
Document Fiscal Period Focus	Q2
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Entity Registrant Name	MUELLER WATER PRODUCTS, INC.
Entity Central Index Key	0001350593
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	false
Amendment Flag	false
Entity Common Stock, Shares Outstanding		157,024,895
Entity Small Business	false
Trading Symbol	MWA
Title of 12(b) Security	$0.01 par value common stock

Cover Page Document

Cover Page Document - shares	6 Months Ended
	Mar. 31, 2022	Apr. 30, 2022
Cover Page [Abstract]
Entity Incorporation, State or Country Code	DE
Document Type	10-Q
Document Type	true
Document Period End Date	Mar. 31, 2022
Document Transition Report	false
Entity File Number	001-32892
Entity Registrant Name	MUELLER WATER PRODUCTS, INC.
Entity Tax Identification Number	20-3547095
Entity Address, Address Line One	1200 Abernathy Road N.E
Entity Address, Address Line Two	Suite 1200
Entity Address, City or Town	Atlanta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30328
City Area Code	(770)
Local Phone Number	206-4200
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		157,024,895
Trading Symbol	MWA
Security Exchange Name	NYSE

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021
Assets:
Receivables, net	$ 222.2	$ 212.2
Inventories	229.2	184.7
Other current assets	31.6	29.3
Total current assets	647.1	653.7
Property, plant and equipment, net	292.3	283.4
Goodwill	115.8	115.1
Identifiable intangible assets	379.4	392.5
Other noncurrent assets	76.9	73.3
Total assets	1,511.5	1,518
Liabilities and stockholders' equity:
Current portion of long-term debt	1	1
Accounts payable	108	92
Accrued liabilities	92.5	127.1
Total current liabilities	201.5	220.1
Long-term debt	446.1	445.9
Deferred income taxes	100.7	95.1
Other noncurrent liabilities	57.1	62
Total liabilities	$ 805.4	$ 823.1
Common Stock, Shares, Outstanding	156,986,382	157,955,433
Common stock	$ 1.6	$ 1.6
Additional paid-in capital	1,307.6	1,342.2
Accumulated deficit	(600.9)	(643.9)
Accumulated other comprehensive income (loss)	(2.2)	(5)
Total equity	706.1	694.9
Total liabilities and stockholders' equity	1,511.5	1,518
Accounts Receivable, Allowance for Credit Loss, Current	4.5	3.5
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 164.1	$ 227.5

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - shares	Mar. 31, 2022	Jun. 30, 2017
Statement of Financial Position [Abstract]
Series A common stock, shares authorized	600,000,000	600,000,000
Series A common stock, shares outstanding	156,986,382

Consolidated Statements Of Oper

Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Net sales	$ 310.5	$ 267.5	$ 582.8	$ 504.9
Cost of sales	217.7	179.1	402.4	338.1
Gross profit	92.8	88.4	180.4	166.8
Operating expenses:
Selling, general and administrative	58	54.2	114.3	103.4
Restructuring and other charges	0.6	0.8	3	2.2
Total operating expenses	58.6	55	117.3	105.6
Operating income	34.2	33.4	63.1	61.2
Non-operating expense:
Pension costs (benefits) other then service	(1)	(0.8)	(2)	(1.6)
Interest expense, net	4.5	6.1	8.8	12.2
Net other expense	3.5	5.3	6.8	10.6
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	30.7	28.1	56.3	50.6
Income tax expense (benefit)	7.1	7.2	13.3	13
Net income (loss)	$ 23.6	$ 20.9	$ 43	$ 37.6
Net income (loss) per basic share:
Earnings Per Share, Basic	$ 0.15	$ 0.13	$ 0.27	$ 0.24
Net income (loss) per diluted share:
Earnings Per Share, Diluted	$ 0.15	$ 0.13	$ 0.27	$ 0.24
Weighted average shares outstanding:
Basic, in shares	156,900	158,400	157,600	158,300
Diluted, in shares	157,500	159,100	158,400	159,000
Dividends declared per share, in dollars per share	$ 0.058	$ 0.055	$ 0.116	$ 0.110

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income Statement - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Net income (loss)	$ 23.6	$ 20.9	$ 43	$ 37.6
Other comprehensive income (loss):
Other comprehensive (income) loss, pension, before tax	0.4	0.6	0.8	1.3
Other comprehensive income (loss), pension income tax effects	0	(0.1)	(0.1)	(0.3)
Foreign currency translation	(3.6)	(0.5)	2.1	4
Other comprehensive income (loss), net of tax	(3.2)	0	2.8	5
Comprehensive income (loss), net of tax	$ 20.4	$ 20.9	$ 45.8	$ 42.6

Consolidated Statement Of Stock

Consolidated Statement Of Stockholders' Equity - USD ($) $ in Millions	Total	Common stock	Accumulated deficit	Accumulated deficitCumulative Effect, Period of Adoption, Adjustment	Accumulated other comprehensive income (loss)	Additional Paid-in Capital [Member]
Other comprehensive income (loss), net of tax					$ 5
Common stock, dividends, per share, declared	$ 0.110
Balance at Sep. 30, 2020		$ 1.6	$ (714.2)		(24.7)	$ 1,378
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared						17.4
Stock-based compensation						3.6
Shares retained for employee taxes						1
Stock repurchased under buyback program						0
Stock issued under stock compensation plans	$ 0					1
Net income (loss)	$ 37.6
Balance at Mar. 31, 2021		1.6	(676.7)		(19.7)	1,364.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent				$ (0.1)
Other comprehensive income (loss), net of tax					0
Common stock, dividends, per share, declared	$ 0.055
Balance at Dec. 31, 2020		1.6	(697.6)		(19.7)	1,370.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared						8.7
Stock-based compensation						1.7
Shares retained for employee taxes						0.1
Stock repurchased under buyback program						0
Stock issued under stock compensation plans	$ 0					0.4
Net income (loss)	20.9
Balance at Mar. 31, 2021		1.6	(676.7)		(19.7)	1,364.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent	669.4			0
Common stock, value, issued	1.6
Other comprehensive income (loss), net of tax	$ 2.8				2.8
Common stock, dividends, per share, declared	$ 0.116
Balance at Sep. 30, 2021	$ 694.9	1.6	(643.9)		(5)	1,342.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared						18.3
Stock-based compensation						4.4
Shares retained for employee taxes						1.8
Stock repurchased under buyback program						(20)
Stock issued under stock compensation plans	0					1.1
Net income (loss)	43
Balance at Mar. 31, 2022	$ 706.1	1.6	(600.9)		(2.2)
Other comprehensive income (loss), net of tax					(3.2)
Common stock, dividends, per share, declared	$ 0.058
Balance at Dec. 31, 2021		1.6	(624.5)		1	1,313.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared						9.1
Stock-based compensation						2.4
Shares retained for employee taxes						(0.1)
Stock repurchased under buyback program						0
Stock issued under stock compensation plans	$ 0					$ 0.4
Net income (loss)	23.6
Balance at Mar. 31, 2022	706.1	$ 1.6	$ (600.9)		$ (2.2)
Common stock, value, issued	1.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent	$ 706.1			$ 0

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows $ in Millions	6 Months Ended
	Mar. 31, 2022USD ($)	Mar. 31, 2021USD ($)
Net cash provided by (used in) operating activities
Net income (loss)	$ 43	$ 37.6
Adjustments to reconcile net income (loss) to income (loss) from continuing operations:
Depreciation	16	15.3
Amortization	14	14.1
Stock-based compensation expense	4.4	3.6
Retirement plans	(1.3)	(1)
Deferred income taxes	6.1	2.4
Inventory write-down	3.3	3.8
Other noncash income (expense)	(0.5)	(0.7)
Changes in assets and liabilities, net of acquisitions:
Receivables	(9.7)	(2.4)
Inventories	(47.5)	(19.7)
Other current assets and other noncurrent assets	(2.4)	1.7
Accounts payable	15.8	7.2
Other current liabilities	(36)	1.2
Long-term liabilities	(5.4)	(1.3)
Net cash provided by (used in) operating activities, total	0.8	63.2
Investing activities:
Capital expenditures	(26)	(31.1)
Payments for (Proceeds from) Other Investing Activities	0.2	0
Proceeds from sales of assets	0	0.3
Net cash provided by (used in) investing activities, total	(25.8)	(30.8)
Financing activities:
Dividends paid	(18.3)	(17.4)
Shares retained for employee taxes	(1.8)	(1)
Common stock issued	1.1	1
Proceeds from Other Equity	0	3.9
Payments of financing costs	0	(0.5)
Stock repurchased under buyback program	(20)	0
Other	(0.1)	(0.5)
Net cash provided by (used in) financing activities, total	(39.1)	(14.5)
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	0.7	1.4
Cash and cash equivalents at beginning of period		208.9
Cash and cash equivalents at end of period		228.2
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	164.1
Interest Paid, Excluding Capitalized Interest, Operating Activities	10.2	12.5
Income Taxes Paid	15.6	4.2
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	$ (63.4)	$ 19.3

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	6 Months Ended
	Mar. 31, 2022
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Comprehensive Income (Loss) Note [Text Block]	Accumulated Other Comprehensive Income (Loss) Accumulated other comprehensive income (loss) is as follows: Pension, net of tax Foreign currency translation Total (in millions) Balance at September 30, 2021 $ (22.2) $ 17.2 $ (5.0) Current period other comprehensive income 0.7 2.1 $ 2.8 Balance at March 31, 2022 $ (21.5) $ 19.3 $ (2.2)
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	Accumulated other comprehensive income (loss) is as follows: Pension, net of tax Foreign currency translation Total (in millions) Balance at September 30, 2021 $ (22.2) $ 17.2 $ (5.0) Current period other comprehensive income 0.7 2.1 $ 2.8 Balance at March 31, 2022 $ (21.5) $ 19.3 $ (2.2)

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tabular)	6 Months Ended
	Mar. 31, 2022
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule Of Accumulated Other Comprehensive Loss	Accumulated other comprehensive income (loss) is as follows: Pension, net of tax Foreign currency translation Total (in millions) Balance at September 30, 2021 $ (22.2) $ 17.2 $ (5.0) Current period other comprehensive income 0.7 2.1 $ 2.8 Balance at March 31, 2022 $ (21.5) $ 19.3 $ (2.2)

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss (Schedule Of Accumulated Other Comprehensive Loss) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2022	Sep. 30, 2021
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	$ (21.5)	$ (21.5)	$ (22.2)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax		0.7
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	19.3	19.3	17.2
Foreign currency translation	(3.6)	2.1
Accumulated other comprehensive income (loss)	$ (2.2)	(2.2)	$ (5)
Other comprehensive income (loss), net of tax		$ 2.8

Organization

Organization	6 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization and Basis of Presentation Mueller Water Products, Inc., a Delaware corporation, together with its consolidated subsidiaries, operates in two business segments: Water Flow Solutions and Water Management Solutions. These segments are based on a management reorganization that became effective October 1, 2021; prior period information has been recast to conform to the current presentation. Water Flow Solutions’ product portfolio includes iron gate valves, specialty valves and service brass products. Water Management Solutions’ product and service portfolio includes fire hydrants, repair and installation, natural gas, metering, leak detection, pressure control and software products. The “Company,” “we,” “us” or “our” refer to Mueller Water Products, Inc. and its subsidiaries, and may also refer to the segment being discussed. On December 3, 2018, we completed our acquisition of Krausz Industries Development Ltd. and subsidiaries (“Krausz”). During the quarter ended March 31, 2021, we aligned the consolidation of the financial statements of Krausz in the Company’s consolidated financial statements, eliminating the previous inclusion of Krausz financial statements with a one-month reporting lag. In accordance with applicable accounting literature, the elimination of the one-month reporting lag is considered to be a change in accounting principle. We believe this change in accounting principle is preferable as the financial statements of all of our subsidiaries are now reported on the same basis, providing the most current information available. The effect of the elimination of the reporting lag during the year ended September 30, 2021 resulted in an increase of $6.0 million to net sales and an increase of $1.4 million to operating income. We concluded that the effect of this change is not material to the balance sheets, statements of operations, statements of cash flows, net income and earnings per share and therefore have not retrospectively applied this change. On June 14, 2021, we acquired all the outstanding capital stock of i2O Water Ltd (“i2O”), a provider of pressure management solutions to more than 100 water companies in 45 countries. The consolidated balance sheet at September 30, 2021 included the preliminary estimated fair values of the net assets of i2O. The accounting for this business combination became final during the three months ended March 31, 2022. The results of i2O’s operations and cash flows subsequent to the acquisition are included in the Company’s consolidated statement of operations and consolidated statement of cash flows, respectively. Refer to Note 2. for additional disclosures related to the acquisition. Our consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”), which require us to make certain estimates and assumptions in recording assets, liabilities, sales and expenses as well as in the disclosure of contingent assets and liabilities. Actual results could differ from those estimates. All significant intercompany balances and transactions have been eliminated. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements included in our Annual Report on Form 10-K for the year ended September 30, 2021. In our opinion, all normal and recurring adjustments that we consider necessary for a fair financial statement presentation have been made. The condensed consolidated balance sheet at September 30, 2021 was derived from audited financial statements, but it does not include all disclosures required by GAAP. Our business is seasonal as a result of cold weather conditions. Net sales and operating income historically have been lowest in the three month periods ending December 31 and March 31 when the northern United States and all of Canada generally face weather conditions that restrict significant construction activity. In preparing these financial statements in conformity with GAAP, we have considered and, where appropriate, included the effects of the COVID-19 pandemic on our operations. The pandemic continues to provide significant challenges to the U.S. and global economies. Unless the context indicates otherwise, whenever we refer to a particular year, we mean our fiscal year ended or ending September 30 in that particular calendar year. Recently Adopted Accounting Guidance During 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Codification (“ASC”) 326 - Current Expected Credit Losses to replace the “incurred loss” impairment approach with an “expected loss” approach, which requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. We completed historical and forward-looking analyses for receivables and adopted this guidance effective October 1, 2020. Upon adoption, there was no material impact to our financial statements. In December 2019, the FASB issued Accounting Standards Update (“ASU”) No. 2019-12, "Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes” (“ASU 2019-12”). ASU 2019-12 simplifies the accounting for income taxes by clarifying and amending existing guidance related to the recognition of franchise tax, the evaluation of a step up in the tax basis of goodwill, and the effects of enacted changes in tax laws or rates in the effective tax rate computation, among other clarifications. ASU 2019-12 is effective for public business entities for fiscal years beginning after December 15, 2020, including interim periods within that fiscal year, with early adoption permitted. We adopted this standard on October 1, 2021 and there was no material impact to our financial statements. In March 2020, the FASB issued ASU No. 2020-04, "Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting" (“ASU 2020-04”). This guidance provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. The amendments apply only to contracts and hedging relationships that reference the London Inter Bank Offered Rate (“LIBOR”) or another reference rate expected to be discontinued due to reference rate reform. ASU 2020-04 is effective from March 12, 2020, but can be adopted prospectively from a date within an interim period subsequent to March 12, 2020. We evaluated our contracts and the optional expedients provided by ASU 2020-04. We adopted this standard on October 1, 2021 and there was no material impact to our financial statements. Restructuring Since November 2019, we have announced the purchase and closure of several facilities. We purchased a new facility in Kimball, Tennessee to support and enhance our investment in our Chattanooga, Tennessee large casting foundry and closed our facilities in Hammond, Indiana, Woodland, Washington and Surrey, British Columbia, Canada. We also announced the closure of our facility in Aurora, Illinois which we expect to complete substantially by the third quarter of fiscal year 2022. The majority of the activities from these facilities have been, or will be, transferred to our Kimball, Tennessee facility. Activity in accrued restructuring, reported as part of Other current liabilities, is presented below. Six months ended March 31, 2022 2021 (in millions) Beginning balance $ 3.1 $ 2.8 Amounts accrued 1.6 1.0 Amounts paid (2.6) (1.6) Ending balance $ 2.1 $ 2.2

Revenue from Contracts with Cus

Revenue from Contracts with Customers (Notes)	6 Months Ended
	Mar. 31, 2022
Revenue from Contracts with Customers [Abstract]
Revenue from Contract with Customer [Text Block]	Revenue from Contracts with Customers We recognize revenue when control of promised products or services is transferred to our customers, in amounts that reflect the consideration to which we expect to be entitled in exchange for those products or services. We account for a contract when it has approval and commitment from both parties, the rights of the parties are identified, the payment terms are identified, the contract has commercial substance and collectability of consideration is probable. We determine the appropriate revenue recognition for our contracts with customers by analyzing the type, terms and conditions of each contract or arrangement with a customer. Disaggregation of Revenue We disaggregate our revenue from contracts with customers by reportable segment (see Note 10.) and further by geographical region as we believe this best depicts how the nature, amount, timing and uncertainty of our revenue and cash flows are affected by economic factors. Geographical region represents the location of the customer. Contract Asset and Liability Balances Differences in the timing of revenue recognition, billing and cash collection result in customer receivables, advance payments and billings in excess of revenue recognized. Customer receivables include amounts billed and currently due from customers as well as unbilled amounts (i.e., contract assets). Amounts are billed in accordance with contractual terms and unbilled amounts arise when the timing of billing differs from the timing of revenue recognized. Advance payments and billings in excess of revenue are recognized and recorded as deferred revenue, the majority of which we expect to receive within one year and therefore is included within Other current liabilities in the accompanying consolidated balance sheets. Deferred revenue represents contract liabilities and are recorded when customers remit cash payments in advance of our satisfaction of performance obligations under contractual arrangements. Contract liabilities are relieved and revenue is recognized when the performance obligation is satisfied. The table below represents the balances of our customer receivables and deferred revenue. March 31, September 30, 2022 2021 (in millions) Billed receivables $ 224.8 $ 213.4 Unbilled receivables 1.9 2.3 Gross customer receivables 226.7 215.7 Allowance for credit losses (4.5) (3.5) Receivables, net $ 222.2 $ 212.2 Deferred revenue $ 7.6 $ 5.4 Performance Obligations A performance obligation is a promise in a contract to transfer a distinct good or service to the customer. Our performance obligations are satisfied at a point in time for sales of product or over time for our software hosting and leak detection monitoring services. Performance obligations are supported by customer contracts, which provide frameworks for the nature of the distinct products or services. We allocate the transaction price of each contract to the performance obligations on the basis of standalone selling price and recognize revenue when control of the performance obligation transfers to the customer. The transaction price is adjusted for our estimate of variable consideration which may include discounts, and rebates. To estimate variable consideration, we apply the expected value or the most likely amount method, based on whichever method most appropriately predicts the amount of consideration we expect to receive. The method applied is based typically on historical experience and known trends. We do not recognize variable consideration in the event there are uncertainties in the amount of variable consideration to be paid nor when it is probable there will be a significant reversal in the related revenue. We exclude from the measurement of the transaction price all taxes assessed by a governmental authority. We classify shipping and handling costs, such as freight to our customers’ destinations, as a component of Cost of sales. We have elected to use the practical expedient to not adjust the transaction price of a contract for the effects of a significant financing component if, at the inception of the contract, we expect that the period between when we transfer a product or service to a customer and when a customer remits payment will be one year or less. The revenue recognized at a point in time related to the sale of our products is recognized when the obligations of the terms of our contract are satisfied, which generally occurs upon shipment when control of the product transfers to the customer. We offer warranties that provide assurance that the products provided will function as intended and comply with any agreed-upon specifications. These cannot be purchased separately. Costs to Obtain or Fulfill a Contract We incur certain incremental costs to obtain a contract, which primarily relate to incremental sales commissions. Our commissions are paid based on a combination of orders and shipments, and we reserve the right to claw back any commissions in case of product returns or lost collections. As the expected benefit associated with these incremental costs is generally one year or less based on the nature of the product sold and benefits received, we have applied a practical expedient and therefore do not capitalize the related costs and expense them as incurred.

Income Taxes

Income Taxes	6 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	Income Taxes The reconciliation between the U.S. federal statutory income tax rate and the effective income tax rate is presented below. Three months ended Six months ended March 31, March 31, 2022 2021 2022 2021 U.S. federal statutory income tax rate 21.0 % 21.0 % 21.0 % 21.0 % Adjustments to reconcile to the effective tax rate: State income taxes, net of federal benefit 3.6 4.2 3.6 4.2 Excess tax benefits related to stock-based compensation — (0.3) (0.2) (0.2) Tax credits (1.3) (1.1) (1.3) (1.1) Global Intangible Low-Taxed Income 0.8 0.6 0.8 0.6 Foreign income tax rate differential (1.4) (0.3) (1.4) (0.3) Valuation allowances (0.3) (0.6) 0.2 (0.2) Other 0.7 2.1 0.9 1.7 Effective income tax rate 23.1 % 25.6 % 23.6 % 25.7 %
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	The reconciliation between the U.S. federal statutory income tax rate and the effective income tax rate is presented below. Three months ended Six months ended March 31, March 31, 2022 2021 2022 2021 U.S. federal statutory income tax rate 21.0 % 21.0 % 21.0 % 21.0 % Adjustments to reconcile to the effective tax rate: State income taxes, net of federal benefit 3.6 4.2 3.6 4.2 Excess tax benefits related to stock-based compensation — (0.3) (0.2) (0.2) Tax credits (1.3) (1.1) (1.3) (1.1) Global Intangible Low-Taxed Income 0.8 0.6 0.8 0.6 Foreign income tax rate differential (1.4) (0.3) (1.4) (0.3) Valuation allowances (0.3) (0.6) 0.2 (0.2) Other 0.7 2.1 0.9 1.7 Effective income tax rate 23.1 % 25.6 % 23.6 % 25.7 %

Borrowing Arrangements

Borrowing Arrangements	6 Months Ended
	Mar. 31, 2022
Long-term Debt and Lease Obligation [Abstract]
Borrowing Arrangements	Borrowing Arrangements The components of our long-term debt are as follows: March 31, September 30, 2022 2021 (in millions) 4.0% Senior Notes $ 450.0 $ 450.0 Finance leases 2.1 2.2 Total borrowings 452.1 452.2 Less deferred financing costs (5.0) (5.3) Less current portion (1.0) (1.0) Long-term debt $ 446.1 $ 445.9 ABL Agreement. Our asset-based lending agreement (“ABL Agreement”) consists of a revolving credit facility for up to $175.0 million which includes up to $25.0 million of swing line loans and may have up to $60.0 million of letters of credit. The ABL Agreement permits us to increase the size of the credit facility by an additional $150.0 million in certain circumstances subject to adequate borrowing base availability. Borrowings under the ABL Agreement bear interest at a floating rate equal to LIBOR plus an applicable margin range of 200 to 225 basis points, or a base rate, as defined in the ABL Agreement, plus an applicable margin range of from 100 to 125 basis points. At March 31, 2022 the applicable margin for LIBOR based loans was 200 basis points and for base rate loans was 100 basis points. The ABL Agreement is subject to mandatory prepayments if total outstanding borrowings under the ABL Agreement are greater than the aggregate commitments under the revolving credit facility or if we dispose of overdue accounts receivable in certain circumstances. The borrowing base under the ABL Agreement is equal to the sum of (a) 85% of the value of eligible accounts receivable and (b) the lesser of (i) 70% of the value of eligible inventory or (ii) 85% of the net orderly liquidation value of eligible inventory, less certain reserves. Prepayments can be made at any time without penalty. Substantially all of our United States subsidiaries are borrowers under the ABL Agreement and are jointly and severally liable for any outstanding borrowings. Our obligations under the ABL Agreement are secured by a first-priority perfected lien on all of our United States inventories, accounts receivable, certain cash and other related items. The ABL Agreement terminates on July 29, 2025 and includes a commitment fee for any unused borrowing capacity of 37.5 basis points per annum. Borrowings are not subject to any financial maintenance covenants unless excess availability is less than the greater of $17.5 million or 10% of the Loan Cap as defined in the ABL Agreement. Excess availability based on March 31, 2022 data was $160.1 million, as reduced by $14.7 million of outstanding letters of credit and $0.2 million of accrued fees and expenses. 4.0% Senior Unsecured Notes. On May 28, 2021, we privately issued $450.0 million of 4.0% Senior Unsecured Notes (“4.0% Senior Notes”), which mature on June 15, 2029 and bear interest at 4.0%, paid semi-annually in June and December. We capitalized $5.5 million of financing costs which are being amortized over the term of the 4.0% Senior Notes using the effective interest method. Substantially all of our U.S. subsidiaries guarantee the 4.0% Senior Notes that are subordinate to borrowings under our ABL Agreement. Based on quoted market prices that are a Level 1 measurement, the outstanding 4.0% Senior Notes had a fair value of $426.0 million at March 31, 2022.

Derivative Financial Instrument

Derivative Financial Instruments (Notes)	6 Months Ended
	Mar. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities Disclosure [Text Block]	Derivative Financial Instruments In connection with the acquisition of Singer Valve in 2017, we loaned funds to one of our Canadian subsidiaries. Although this intercompany loan had no direct effect on our consolidated financial statements, it created exposure to currency risk for the Canadian subsidiary. To reduce this exposure, we entered into a U.S. dollar-Canadian dollar swap contract with the Canadian subsidiary and an offsetting Canadian dollar-U.S. dollar swap with a domestic bank. We did not designate these swaps as hedges and the changes in their fair value were included in earnings, offsetting the currency gains and losses associated with the intercompany loan. The value of our currency swap contracts as of September 30, 2021 was a liability of $1.1 million, and was included in Other current liabilities.

Retirement Plans

Retirement Plans	6 Months Ended
	Mar. 31, 2022
Retirement Benefits [Abstract]
Retirement Plans	Retirement Plans The components of net periodic benefit cost for our pension plans are presented below. Three months ended Six months ended March 31, March 31, 2022 2021 2022 2021 (in millions) Service cost $ 0.3 $ 0.4 $ 0.6 $ 0.8 Pension costs (benefits) other than service: Interest cost 2.4 2.5 4.8 5.0 Expected return on plan assets (3.8) (3.9) (7.6) (7.8) Amortization of actuarial net loss 0.4 0.6 0.8 1.2 Pension benefits other than service (1.0) (0.8) (2.0) (1.6) Net periodic benefit $ (0.7) $ (0.4) $ (1.4) $ (0.8) The amortization of actuarial losses, net of tax, is recorded as a component of other comprehensive income (loss).

Stock-based Compensation Plans

Stock-based Compensation Plans	6 Months Ended
	Mar. 31, 2022
Share-based Payment Arrangement, Noncash Expense [Abstract]
Share-based Payment Arrangement [Text Block]	Stock-based Compensation Plans We grant various forms of stock-based compensation, including market-based restricted stock units (“MRSUs”), restricted stock units, stock options and performance-based restricted stock units (“PRSUs”) under our Amended and Restated 2006 Mueller Water Products, Inc. Stock Incentive Plan (the “2006 Stock Plan”), Phantom Plan instruments under our Mueller Water Products, Inc. 2012 Phantom Plan, and Employee stock purchase plan instruments under our 2006 Employee Stock Purchase Plan. Grants issued during the six months ended March 31, 2022 are as follows: Number granted Weighted average grant date fair value per instrument Total grant date fair value Quarter ended December 31, 2021 MRSUs 230,089 $ 15.76 $ 3.6 Phantom Plan instruments 199,549 13.64 2.7 Restricted stock units 135,129 13.64 1.8 Non-qualified stock options 457,482 3.43 1.6 PRSUs: 2020 award 57,627 13.81 0.8 Employee stock purchase plan instruments 38,069 3.01 0.1 Quarter ended March 31, 2022 Restricted stock units 88,250 13.03 1.1 Employee stock purchase plan instruments 38,512 3.39 0.1 $ 11.8 An MRSU award represents a target number of units that may be paid out at the end of a three-year award cycle based on a calculation of our relative total shareholder return (“TSR”) performance as compared with the TSR of a selected peer group. Settlements, in our common shares, will range from zero to two times the number of MRSUs granted, depending on our TSR performance relative to that of the peer group. Compensation expense attributed to MRSUs is based on the fair value of the awards on their respective grant dates, as determined using a Monte Carlo model. The assumptions used to determine the grant date fair value are indicated below. November 30, 2021 Variables used in determining grant date fair value: Dividend yield 1.70 % Risk-free rate 0.76 % Expected term (in years) 2.83 The expected dividend yield is based on our estimated annual dividend and our stock price history at the grant date. The risk-free interest rate is based on the U.S. Treasury zero-coupon yield in effect at the grant date with a term equal to the expected term. The expected term represents the average period of time the units are expected to be outstanding. At March 31, 2022, the outstanding Phantom Plan instruments had a fair value of $12.92 per instrument and our liability for Phantom Plan instruments was $2.1 million and is included within Other current and Other noncurrent liabilities. Stock options generally vest ratably over three years on each anniversary date. Compensation expense attributed to stock options is based on the fair value of the awards on their respective grant dates, using a Black-Scholes model. The assumptions used to determine the grant date fair value are indicated below. November 30, 2021 Dividend yield 1.62 % Risk-free rate 1.33 % Expected term (in years) 6.00 The expected dividend yield is based on our estimated annual dividend and our stock price history at the grant date. The risk-free interest rate is based on the U.S. Treasury zero-coupon yield in effect at the grant date with a term equal to the expected term. The expected term represents the average period of time the options are expected to be outstanding. A PRSU award consists of a number of units that may be paid out at the end of a three-year award cycle consisting of a series of annual performance periods coinciding with our fiscal years. After we establish the financial performance targets related to PRSUs for a given performance period, typically during the first quarter of that fiscal year, we consider that portion of a PRSU award to be granted. Thus, each award consists of a grant in the year of award and grants in the two following years. Settlements, in our common shares, will range from zero to two times the number of PRSUs granted, depending on our financial performance relative to the targets. We did not issue any shares of common stock to settle PRSUs vested during the three months ended March 31, 2022; however, we issued 240,412 shares of common stock to settle PRSUs vested during the six months ended March 31, 2022. Additionally, we issued 104,380 and 235,095 shares of common stock to settle restricted stock units vested during the three and six months ended March 31, 2022, respectively. Finally, we issued no shares of common stock to settle stock options exercised during the three months ended March 31, 2022; however, we issued 24,153 shares of common stock to settle stock options exercised during the six months ended March 31, 2022. Operating income included stock-based compensation expense of $2.5 million in each of the three months ended March 31, 2022 and 2021. Operating income included stock-based compensation expense of $5.1 million and $5.0 million during the six months ended March 31, 2022 and 2021, respectively. At March 31, 2022, there was approximately $13.3 million of unrecognized compensation expense related to stock-based compensation arrangements and there were 58,139 PRSUs that have been awarded for the 2022 performance period for which performance goal achievement cannot yet be determined. We excluded 944,631 and 664,082 stock-based compensation instruments from the calculations of diluted earnings per share in the three months ended March 31, 2022 and 2021, respectively, and 563,299 and 447,086 for the six months ended March 31, 2022 and 2021, respectively, since their inclusion would have been antidilutive.

Supplemental Balance Sheet Info

Supplemental Balance Sheet Information	3 Months Ended
	Mar. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Supplemental Balance Sheet Information	Supplemental Balance Sheet Information Selected supplemental asset information is presented below. March 31, September 30, 2022 2021 (in millions) Inventories: Purchased components and raw material $ 137.4 $ 100.9 Work in process, net 46.4 41.6 Finished goods, net 45.4 42.2 Total inventories $ 229.2 $ 184.7 Other current assets: Prepaid expenses $ 13.1 $ 12.8 Non-trade receivables 10.7 10.7 Maintenance and repair supplies and tooling 2.3 2.9 Income taxes 0.2 0.2 Workers’compensation reimbursement receivable 1.7 0.8 Other current assets 3.6 1.9 Total other current assets $ 31.6 $ 29.3 Property, plant and equipment: Land $ 5.5 $ 6.1 Buildings 86.7 84.6 Machinery and equipment 446.1 433.3 Construction in progress 93.0 83.7 Total property, plant and equipment 631.3 607.7 Accumulated depreciation (339.0) (324.3) Property, plant and equipment, net $ 292.3 $ 283.4 Other noncurrent assets: Operating lease right-of-use assets $ 25.7 $ 27.1 Maintenance and repair supplies and tooling 20.5 19.3 Workers’ compensation reimbursement receivable 5.0 2.7 Pension asset 19.0 16.8 Note receivable 1.8 1.8 Deferred financing fees 1.1 1.3 Other noncurrent assets 3.8 4.3 Total other noncurrent assets $ 76.9 $ 73.3 Selected supplemental liability information is presented below. March 31, September 30, 2022 2021 (in millions) Other current liabilities: Compensation and benefits $ 32.4 $ 44.6 Customer rebates 7.7 19.6 Warranty accrual 5.9 6.7 Deferred revenue 7.6 5.4 Refund liability 5.2 6.0 Taxes other than income taxes 5.5 4.4 Operating lease liabilities 3.8 4.0 Workers’ compensation accrual 3.1 2.6 CARES Act payroll tax liabilities 3.6 3.6 Restructuring liabilities 2.1 3.1 Environmental liabilities 1.2 1.2 Interest payable 5.3 6.2 Income taxes payable 1.7 8.5 Other current liabilities 7.4 11.2 Total other current liabilities $ 92.5 $ 127.1 Other noncurrent liabilities: Operating lease liabilities $ 23.0 $ 24.6 Warranty accrual 1.7 3.0 Transition tax liability 4.1 4.7 Uncertain tax position liability 4.7 4.8 NMTC liability 3.9 3.9 Workers’ compensation accrual 10.6 7.9 Asset retirement obligation 3.6 3.6 CARES Act payroll tax liabilities — 3.6 Deferred development grant 2.5 2.5 Other noncurrent liabilities 3.0 3.4 Total other noncurrent liabilities $ 57.1 $ 62.0 Goodwill Goodwill is tested for impairment at the reporting unit level (operating segment or one level below an operating segment) on an annual basis each September 1 st and between annual tests if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying value. The following table summarizes information concerning our goodwill balance in the six months ended March 31, 2022, in millions. Balance at September 30, 2021 $ 115.1 Acquisition adjustments 0.1 Effects of changes in foreign currency exchange rates 0.6 Balance at March 31, 2022 $ 115.8

Segment Information

Segment Information	6 Months Ended
	Mar. 31, 2022
Segment Reporting, Measurement Disclosures [Abstract]
Segment Reporting Disclosure [Text Block]	Segment Information We adopted a new management structure effective October 1, 2021 which resulted in a change to our reportable segments. Prior period information has been recast to conform to the current presentation. The recasting has no effect on our previously reported consolidated balance sheets, consolidated statements of operations, or consolidated statements of cash flows. The two newly named business units and reportable segments are Water Flow Solutions and Water Management Solutions. Water Flow Solutions’ product portfolio includes iron gate valves, specialty valves and service brass products. Water Management Solutions’ product and service portfolio includes fire hydrants, repair and installation, natural gas, metering, leak detection, pressure control and software products. Summarized financial information for our segments is presented below. Three months ended Six months ended March 31, March 31, 2022 2021 2022 2021 (in millions) Net sales, excluding intercompany: Water Flow Solutions $ 183.9 $ 147.1 $ 338.8 $ 275.9 Water Management Solutions 126.6 120.4 244.0 229.0 $ 310.5 $ 267.5 $ 582.8 $ 504.9 Operating income (loss): Water Flow Solutions $ 35.4 $ 29.7 $ 66.7 $ 52.8 Water Management Solutions 11.7 18.3 23.2 35.3 Corporate (12.9) (14.6) (26.8) (26.9) $ 34.2 $ 33.4 $ 63.1 $ 61.2 Depreciation and amortization: Water Flow Solutions $ 7.5 $ 7.5 $ 14.9 $ 14.9 Water Management Solutions 7.3 7.2 15.0 14.4 Corporate — — 0.1 0.1 $ 14.8 $ 14.7 $ 30.0 $ 29.4 Strategic reorganization and other charges: Water Flow Solutions $ — $ — $ — $ 0.1 Water Management Solutions 0.1 (0.7) 0.1 (0.7) Corporate 0.5 1.5 2.9 2.8 $ 0.6 $ 0.8 $ 3.0 $ 2.2 Capital expenditures: Water Flow Solutions $ 12.1 $ 13.8 $ 21.5 $ 26.1 Water Management Solutions 2.9 1.7 4.5 4.9 Corporate — — — 0.1 $ 15.0 $ 15.5 $ 26.0 $ 31.1 Water Flow Solutions disaggregated net revenue: Central $ 50.7 $ 38.4 $ 91.2 $ 73.4 Northeast 31.1 22.4 61.1 47.3 Southeast 40.7 29.9 78.0 53.0 West 45.8 43.4 83.9 79.7 United States 168.3 134.1 314.2 253.4 Canada 14.0 11.1 21.9 16.8 Other international locations 1.6 1.9 2.7 5.7 $ 183.9 $ 147.1 $ 338.8 $ 275.9 Water Management Solutions disaggregated net revenue: Central $ 34.6 $ 32.3 $ 63.4 $ 59.2 Northeast 28.4 24.2 52.7 48.6 Southeast 26.3 24.7 51.8 47.5 West 22.3 23.1 47.0 45.2 United States 111.6 104.3 214.9 200.5 Canada 8.7 9.4 16.3 16.1 Other international locations 6.3 6.7 12.8 12.4 $ 126.6 $ 120.4 $ 244.0 $ 229.0

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	Commitments and Contingencies We are involved in various legal proceedings that have arisen in the normal course of operations, including the proceedings summarized below. We provide for costs relating to these matters when a loss is probable and the amount is reasonably estimable. Legal costs related to these matters are expensed as incurred. The effect of the outcome of these matters on our financial statements cannot be predicted with certainty as any such effect depends on the amount and timing of the resolution of such matters. Other than the litigation described below, we do not believe that any of our outstanding litigation would have a materially adverse effect on our financial position, results of operations, cash flows or liquidity. Environmental. We are subject to a wide variety of laws and regulations concerning the protection of the environment, both with respect to the operations at many of our properties and with respect to remediating environmental conditions that may exist at our own or other properties. We accrue for environmental expenses resulting from existing conditions that relate to past operations when the costs are probable and reasonably estimable. In the acquisition agreement pursuant to which a predecessor to Tyco International plc, now Johnson Controls International plc (“Tyco”), sold our businesses to a previous owner in August 1999, Tyco agreed to indemnify us and our affiliates, among other things, for all “Excluded Liabilities.” Excluded Liabilities include, among other things, substantially all liabilities relating to the time prior to August 1999, including environmental liabilities. The indemnity survives indefinitely. Tyco’s indemnity does not cover liabilities to the extent caused by us or the operation of our businesses after August 1999, nor does it cover liabilities arising with respect to businesses or sites acquired after August 1999. Since 2007, Tyco has engaged in multiple corporate restructurings, split-offs and divestitures. While none of these transactions directly affects the indemnification obligations of the Tyco indemnitors under the 1999 acquisition agreement, the result of such transactions is that the assets of, and control over, such Tyco indemnitors has changed. Should any of these Tyco indemnitors become financially unable or fail to comply with the terms of the indemnity, we may be responsible for such obligations or liabilities. On July 13, 2010, Rohcan Investments Limited, the former owner of property leased by Mueller Canada Ltd. and located in Milton, Ontario, filed suit against Mueller Canada Ltd. and its directors seeking C$10.0 million in damages arising from the defendants’ alleged environmental contamination of the property and breach of lease. Mueller Canada Ltd. leased the property from 1988 through 2008. We are pursuing indemnification from a former owner for certain potential liabilities that are alleged in this lawsuit, and we have accrued for other liabilities not covered by indemnification. On December 7, 2011, the Court denied the plaintiff’s motion for summary judgment. The purchaser of U.S. Pipe has been identified as a “potentially responsible party” (“PRP”) under the Comprehensive Environmental Response, Compensation and Liability Act in connection with a former manufacturing facility operated by U.S. Pipe that was in the vicinity of a proposed Superfund site located in North Birmingham, Alabama. Under the terms of the acquisition agreement relating to our sale of U.S. Pipe, we agreed to indemnify the purchaser for certain environmental liabilities, including those arising out of the former manufacturing site in North Birmingham. Accordingly, the purchaser tendered the matter to us for indemnification, which we accepted. Ultimate liability for the site will depend on many factors that have not yet been determined, including the determination of the Environmental Protection Agency’s remediation costs, the number and financial viability of the other PRPs (there are four other PRPs currently) and the determination of the final allocation of the costs among the PRPs. Since the amounts of such costs cannot be reasonably estimated at this time, no amounts have been accrued for this matter at March 31, 2022. The COVID-19 Pandemic. The pandemic has caused, and is likely to continue to cause, severe economic, market and other disruptions to the U.S. and global economies. We have taken action and continue to counter such disruption, and work to protect the safety of our employees. We are uncertain of the potential full magnitude or duration of the business and economic impacts from the unprecedented public health effort to contain and combat the spread of COVID-19, and while the extent to which the pandemic affects our results will depend on future developments, the outbreak could result in material effects to our future financial position, results of operations, cash flows and liquidity. Mass Shooting Event at our Mueller Co. Facility in Albertville, Alabama. On June 15, 2021, we experienced a mass shooting event at our Mueller Co. facility in Albertville, Alabama, in which two employees were killed and two employees were injured. Various claims arising from the event have been filed to date and we anticipate that additional claims may be made and that liability under such claims, if any, is not expected to have a material adverse effect on our results of operations or cash flows. However, the outcome of these claims, or legal proceedings, and related effects arising from this event cannot be predicted with certainty. Indemnifications . We are a party to contracts in which it is common for us to agree to indemnify third parties for certain liabilities that arise out of or relate to the subject matter of the contract. In some cases, this indemnity extends to related liabilities arising from the negligence of the indemnified parties, but usually excludes any liabilities caused by gross negligence or willful misconduct. We cannot estimate the potential amount of future payments under these indemnities until events arise that would trigger a liability under the indemnities. Additionally, in connection with the sale of assets and the divestiture of businesses, such as the divestitures of U.S. Pipe and Anvil, we may agree to indemnify buyers and related parties for certain losses or liabilities incurred by these parties with respect to: (i) the representations and warranties made by us to these parties in connection with the sale and (ii) liabilities related to the pre-closing operations of the assets or business sold. Indemnities related to pre-closing operations generally include certain environmental and tax liabilities and other liabilities not assumed by these parties in the transaction. Indemnities related to the pre-closing operations of sold assets or businesses normally do not represent additional liabilities to us, but simply serve to protect these parties from potential liability associated with our obligations existing at the time of the sale. As with any liability, we have accrued for those pre-closing obligations that are considered probable and reasonably estimable. Should circumstances change, increasing the likelihood of payments related to a specific indemnity, we will accrue a liability when future payment is probable and the amount is reasonably estimable. Other Matters. We monitor and analyze our warranty experience and costs periodically and may revise our accruals as necessary. Critical factors in our analyses include warranty terms, specific claim situations, general incurred and projected failure rates, the nature of product failures, product and labor costs, and general business conditions. We are party to a number of lawsuits arising in the ordinary course of business, including product liability cases for products manufactured by us or third parties. While the results of litigation cannot be predicted with certainty, we believe that the final outcome of such other litigation is not likely to have a materially adverse effect on our financial position, results of operations, cash flows or liquidity.

Subsequent Events

Subsequent Events	6 Months Ended
	Mar. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On April 22, 2022, our Board of Directors declared a dividend of $0.058 per share on our common stock, payable on or about May 20, 2022 to stockholders of record at the close of business on May 10, 2022

Business Combinations and Asset

Business Combinations and Asset Acquisitions	3 Months Ended
	Mar. 31, 2022
Acquistions [Abstract]
Business Combination Disclosure [Text Block]	Acquisitions Acquisition of i2O Water Ltd On June 14, 2021, we acquired all the outstanding capital stock of i2O for $19.7 million, net of cash acquired. The purchase agreement provided for customary final adjustments, including a net working capital adjustment that was completed during the three months ended December 31, 2021, resulting in a purchase price of $19.5 million. We have recognized the assets acquired and liabilities assumed at their estimated acquisition date fair values, with the excess of the purchase price over the estimated fair values of the identifiable net assets acquired recorded as goodwill. The accounting for the business combination is considered to be final. The results of i2O are included in our Water Management Solutions segment. The goodwill below is attributable to the strategic opportunities and synergies that we expect to arise from the acquisition of i2O and the value of its workforce. Goodwill is nondeductible for income tax purposes. Identified intangible assets consist of customer relationships, non-compete agreements and developed technology with an estimated weighted-average useful life of approximately 12 years and trade names with an indefinite life. Values of intangible assets were determined using a discounted cash flow method. The following is a summary of the fair values of the net assets acquired (in millions): Assets, net of cash: Receivables $ 0.5 Inventories 0.6 Other current assets 0.9 Identified intangible assets: Tradename 1.8 Customer relationships 2.1 Non-compete agreements 0.1 Developed technology 3.5 Goodwill 12.1 Liabilities: Accounts payable (0.8) Other current liabilities (1.3) Fair value of net assets acquired, net of cash $ 19.5

Organization Restructuring Roll

Organization Restructuring Rollforward (Tables)	6 Months Ended
	Mar. 31, 2022
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Costs [Table Text Block]	Activity in accrued restructuring, reported as part of Other current liabilities, is presented below. Six months ended March 31, 2022 2021 (in millions) Beginning balance $ 3.1 $ 2.8 Amounts accrued 1.6 1.0 Amounts paid (2.6) (1.6) Ending balance $ 2.1 $ 2.2

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	6 Months Ended
	Mar. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Schedule of Accounts, Notes, Loans and Financing Receivable	e table below represents the balances of our customer receivables and deferred revenue. March 31, September 30, 2022 2021 (in millions) Billed receivables $ 224.8 $ 213.4 Unbilled receivables 1.9 2.3 Gross customer receivables 226.7 215.7 Allowance for credit losses (4.5) (3.5) Receivables, net $ 222.2 $ 212.2 Deferred revenue $ 7.6 $ 5.4

Income Taxes Rate Reconciliatio

Income Taxes Rate Reconciliation (Tables)	6 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	The reconciliation between the U.S. federal statutory income tax rate and the effective income tax rate is presented below. Three months ended Six months ended March 31, March 31, 2022 2021 2022 2021 U.S. federal statutory income tax rate 21.0 % 21.0 % 21.0 % 21.0 % Adjustments to reconcile to the effective tax rate: State income taxes, net of federal benefit 3.6 4.2 3.6 4.2 Excess tax benefits related to stock-based compensation — (0.3) (0.2) (0.2) Tax credits (1.3) (1.1) (1.3) (1.1) Global Intangible Low-Taxed Income 0.8 0.6 0.8 0.6 Foreign income tax rate differential (1.4) (0.3) (1.4) (0.3) Valuation allowances (0.3) (0.6) 0.2 (0.2) Other 0.7 2.1 0.9 1.7 Effective income tax rate 23.1 % 25.6 % 23.6 % 25.7 %

Borrowing Arrangements (Tables)

Borrowing Arrangements (Tables)	6 Months Ended
	Mar. 31, 2022
Long-term Debt and Lease Obligation [Abstract]
Components of Long-Term Debt	The components of our long-term debt are as follows: March 31, September 30, 2022 2021 (in millions) 4.0% Senior Notes $ 450.0 $ 450.0 Finance leases 2.1 2.2 Total borrowings 452.1 452.2 Less deferred financing costs (5.0) (5.3) Less current portion (1.0) (1.0) Long-term debt $ 446.1 $ 445.9

Retirement Plans (Tables)

Retirement Plans (Tables)	6 Months Ended
	Mar. 31, 2022
Retirement Benefits [Abstract]
Schedule of Net Periodic Benefit Cost	The components of net periodic benefit cost for our pension plans are presented below. Three months ended Six months ended March 31, March 31, 2022 2021 2022 2021 (in millions) Service cost $ 0.3 $ 0.4 $ 0.6 $ 0.8 Pension costs (benefits) other than service: Interest cost 2.4 2.5 4.8 5.0 Expected return on plan assets (3.8) (3.9) (7.6) (7.8) Amortization of actuarial net loss 0.4 0.6 0.8 1.2 Pension benefits other than service (1.0) (0.8) (2.0) (1.6) Net periodic benefit $ (0.7) $ (0.4) $ (1.4) $ (0.8)

Stock-based Compensation Plans

Stock-based Compensation Plans (Tables)	3 Months Ended
	Mar. 31, 2022
Share-based Payment Arrangement, Noncash Expense [Abstract]
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	Stock options generally vest ratably over three years on each anniversary date. Compensation expense attributed to stock options is based on the fair value of the awards on their respective grant dates, using a Black-Scholes model. The assumptions used to determine the grant date fair value are indicated below. November 30, 2021 Dividend yield 1.62 % Risk-free rate 1.33 % Expected term (in years) 6.00

Supplemental Balance Sheet In_2

Supplemental Balance Sheet Information (Tables)	3 Months Ended
	Mar. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Schedule Of Selected Supplemental Balance Sheet Information [Table Text Block]	Selected supplemental asset information is presented below. March 31, September 30, 2022 2021 (in millions) Inventories: Purchased components and raw material $ 137.4 $ 100.9 Work in process, net 46.4 41.6 Finished goods, net 45.4 42.2 Total inventories $ 229.2 $ 184.7 Other current assets: Prepaid expenses $ 13.1 $ 12.8 Non-trade receivables 10.7 10.7 Maintenance and repair supplies and tooling 2.3 2.9 Income taxes 0.2 0.2 Workers’compensation reimbursement receivable 1.7 0.8 Other current assets 3.6 1.9 Total other current assets $ 31.6 $ 29.3 Property, plant and equipment: Land $ 5.5 $ 6.1 Buildings 86.7 84.6 Machinery and equipment 446.1 433.3 Construction in progress 93.0 83.7 Total property, plant and equipment 631.3 607.7 Accumulated depreciation (339.0) (324.3) Property, plant and equipment, net $ 292.3 $ 283.4 Other noncurrent assets: Operating lease right-of-use assets $ 25.7 $ 27.1 Maintenance and repair supplies and tooling 20.5 19.3 Workers’ compensation reimbursement receivable 5.0 2.7 Pension asset 19.0 16.8 Note receivable 1.8 1.8 Deferred financing fees 1.1 1.3 Other noncurrent assets 3.8 4.3 Total other noncurrent assets $ 76.9 $ 73.3
Schedule of Accrued Liabilities	Selected supplemental liability information is presented below. March 31, September 30, 2022 2021 (in millions) Other current liabilities: Compensation and benefits $ 32.4 $ 44.6 Customer rebates 7.7 19.6 Warranty accrual 5.9 6.7 Deferred revenue 7.6 5.4 Refund liability 5.2 6.0 Taxes other than income taxes 5.5 4.4 Operating lease liabilities 3.8 4.0 Workers’ compensation accrual 3.1 2.6 CARES Act payroll tax liabilities 3.6 3.6 Restructuring liabilities 2.1 3.1 Environmental liabilities 1.2 1.2 Interest payable 5.3 6.2 Income taxes payable 1.7 8.5 Other current liabilities 7.4 11.2 Total other current liabilities $ 92.5 $ 127.1 Other noncurrent liabilities: Operating lease liabilities $ 23.0 $ 24.6 Warranty accrual 1.7 3.0 Transition tax liability 4.1 4.7 Uncertain tax position liability 4.7 4.8 NMTC liability 3.9 3.9 Workers’ compensation accrual 10.6 7.9 Asset retirement obligation 3.6 3.6 CARES Act payroll tax liabilities — 3.6 Deferred development grant 2.5 2.5 Other noncurrent liabilities 3.0 3.4 Total other noncurrent liabilities $ 57.1 $ 62.0
Schedule of Goodwill	The following table summarizes information concerning our goodwill balance in the six months ended March 31, 2022, in millions. Balance at September 30, 2021 $ 115.1 Acquisition adjustments 0.1 Effects of changes in foreign currency exchange rates 0.6 Balance at March 31, 2022 $ 115.8

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Mar. 31, 2022
Segment Reporting, Measurement Disclosures [Abstract]
Schedule Of Selected Supplemental Balance Sheet Information	mmarized financial information for our segments is presented below. Three months ended Six months ended March 31, March 31, 2022 2021 2022 2021 (in millions) Net sales, excluding intercompany: Water Flow Solutions $ 183.9 $ 147.1 $ 338.8 $ 275.9 Water Management Solutions 126.6 120.4 244.0 229.0 $ 310.5 $ 267.5 $ 582.8 $ 504.9 Operating income (loss): Water Flow Solutions $ 35.4 $ 29.7 $ 66.7 $ 52.8 Water Management Solutions 11.7 18.3 23.2 35.3 Corporate (12.9) (14.6) (26.8) (26.9) $ 34.2 $ 33.4 $ 63.1 $ 61.2 Depreciation and amortization: Water Flow Solutions $ 7.5 $ 7.5 $ 14.9 $ 14.9 Water Management Solutions 7.3 7.2 15.0 14.4 Corporate — — 0.1 0.1 $ 14.8 $ 14.7 $ 30.0 $ 29.4 Strategic reorganization and other charges: Water Flow Solutions $ — $ — $ — $ 0.1 Water Management Solutions 0.1 (0.7) 0.1 (0.7) Corporate 0.5 1.5 2.9 2.8 $ 0.6 $ 0.8 $ 3.0 $ 2.2 Capital expenditures: Water Flow Solutions $ 12.1 $ 13.8 $ 21.5 $ 26.1 Water Management Solutions 2.9 1.7 4.5 4.9 Corporate — — — 0.1 $ 15.0 $ 15.5 $ 26.0 $ 31.1 Water Flow Solutions disaggregated net revenue: Central $ 50.7 $ 38.4 $ 91.2 $ 73.4 Northeast 31.1 22.4 61.1 47.3 Southeast 40.7 29.9 78.0 53.0 West 45.8 43.4 83.9 79.7 United States 168.3 134.1 314.2 253.4 Canada 14.0 11.1 21.9 16.8 Other international locations 1.6 1.9 2.7 5.7 $ 183.9 $ 147.1 $ 338.8 $ 275.9 Water Management Solutions disaggregated net revenue: Central $ 34.6 $ 32.3 $ 63.4 $ 59.2 Northeast 28.4 24.2 52.7 48.6 Southeast 26.3 24.7 51.8 47.5 West 22.3 23.1 47.0 45.2 United States 111.6 104.3 214.9 200.5 Canada 8.7 9.4 16.3 16.1 Other international locations 6.3 6.7 12.8 12.4 $ 126.6 $ 120.4 $ 244.0 $ 229.0

Business Combinations and Ass_2

Business Combinations and Asset Acquisitions (Tables)	6 Months Ended
	Mar. 31, 2022
Acquistions [Abstract]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	The following is a summary of the fair values of the net assets acquired (in millions): Assets, net of cash: Receivables $ 0.5 Inventories 0.6 Other current assets 0.9 Identified intangible assets: Tradename 1.8 Customer relationships 2.1 Non-compete agreements 0.1 Developed technology 3.5 Goodwill 12.1 Liabilities: Accounts payable (0.8) Other current liabilities (1.3) Fair value of net assets acquired, net of cash $ 19.5

Organization (Details)

Organization (Details) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022USD ($)business_segments	Mar. 31, 2021USD ($)	Mar. 31, 2022USD ($)	Mar. 31, 2021USD ($)	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)
Segment Reporting Information [Line Items]
Restructuring	$ 2.1	$ 2.2	$ 2.1	$ 2.2	$ 3.1	$ 2.8
Restructuring and other charges	0.6	0.8	3	2.2
Payments			2.6	1.6
Pension costs (benefits) other then service	$ (1)	$ (0.8)	$ (2)	$ (1.6)
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	21.00%	21.00%
Number of Reportable Segments | business_segments	2
Proceeds from Other Equity, Gross Amount	$ 4.8		$ 4.8
Intercompany Loan related to NMTC	12.2		12.2
Investment Fund Contribution for NMTC	16.5		16.5
Sub-CDE loan from NMTC	16.2		16.2
Mueller Co. [Member]
Segment Reporting Information [Line Items]
Restructuring and other charges	$ 0	$ 0	$ 0	$ 0.1

Organization Restructuring (Det

Organization Restructuring (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021	Sep. 30, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring	$ 2.1	$ 2.2	$ 2.1	$ 2.2	$ 3.1	$ 2.8
Restructuring and other charges	$ 0.6	$ 0.8	3	2.2
Payments			(2.6)	(1.6)
Mueller One Project [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges			$ 1.6	$ 1

Revenue from Contracts with C_3

Revenue from Contracts with Customers (Details) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2022	Sep. 30, 2021
Revenue from External Customer [Line Items]
Revenue from Contract with Customer [Text Block]	Revenue from Contracts with Customers We recognize revenue when control of promised products or services is transferred to our customers, in amounts that reflect the consideration to which we expect to be entitled in exchange for those products or services. We account for a contract when it has approval and commitment from both parties, the rights of the parties are identified, the payment terms are identified, the contract has commercial substance and collectability of consideration is probable. We determine the appropriate revenue recognition for our contracts with customers by analyzing the type, terms and conditions of each contract or arrangement with a customer. Disaggregation of Revenue We disaggregate our revenue from contracts with customers by reportable segment (see Note 10.) and further by geographical region as we believe this best depicts how the nature, amount, timing and uncertainty of our revenue and cash flows are affected by economic factors. Geographical region represents the location of the customer. Contract Asset and Liability Balances Differences in the timing of revenue recognition, billing and cash collection result in customer receivables, advance payments and billings in excess of revenue recognized. Customer receivables include amounts billed and currently due from customers as well as unbilled amounts (i.e., contract assets). Amounts are billed in accordance with contractual terms and unbilled amounts arise when the timing of billing differs from the timing of revenue recognized. Advance payments and billings in excess of revenue are recognized and recorded as deferred revenue, the majority of which we expect to receive within one year and therefore is included within Other current liabilities in the accompanying consolidated balance sheets. Deferred revenue represents contract liabilities and are recorded when customers remit cash payments in advance of our satisfaction of performance obligations under contractual arrangements. Contract liabilities are relieved and revenue is recognized when the performance obligation is satisfied. The table below represents the balances of our customer receivables and deferred revenue. March 31, September 30, 2022 2021 (in millions) Billed receivables $ 224.8 $ 213.4 Unbilled receivables 1.9 2.3 Gross customer receivables 226.7 215.7 Allowance for credit losses (4.5) (3.5) Receivables, net $ 222.2 $ 212.2 Deferred revenue $ 7.6 $ 5.4 Performance Obligations A performance obligation is a promise in a contract to transfer a distinct good or service to the customer. Our performance obligations are satisfied at a point in time for sales of product or over time for our software hosting and leak detection monitoring services. Performance obligations are supported by customer contracts, which provide frameworks for the nature of the distinct products or services. We allocate the transaction price of each contract to the performance obligations on the basis of standalone selling price and recognize revenue when control of the performance obligation transfers to the customer. The transaction price is adjusted for our estimate of variable consideration which may include discounts, and rebates. To estimate variable consideration, we apply the expected value or the most likely amount method, based on whichever method most appropriately predicts the amount of consideration we expect to receive. The method applied is based typically on historical experience and known trends. We do not recognize variable consideration in the event there are uncertainties in the amount of variable consideration to be paid nor when it is probable there will be a significant reversal in the related revenue. We exclude from the measurement of the transaction price all taxes assessed by a governmental authority. We classify shipping and handling costs, such as freight to our customers’ destinations, as a component of Cost of sales. We have elected to use the practical expedient to not adjust the transaction price of a contract for the effects of a significant financing component if, at the inception of the contract, we expect that the period between when we transfer a product or service to a customer and when a customer remits payment will be one year or less. The revenue recognized at a point in time related to the sale of our products is recognized when the obligations of the terms of our contract are satisfied, which generally occurs upon shipment when control of the product transfers to the customer. We offer warranties that provide assurance that the products provided will function as intended and comply with any agreed-upon specifications. These cannot be purchased separately. Costs to Obtain or Fulfill a Contract We incur certain incremental costs to obtain a contract, which primarily relate to incremental sales commissions. Our commissions are paid based on a combination of orders and shipments, and we reserve the right to claw back any commissions in case of product returns or lost collections. As the expected benefit associated with these incremental costs is generally one year or less based on the nature of the product sold and benefits received, we have applied a practical expedient and therefore do not capitalize the related costs and expense them as incurred.
Billed Contracts Receivable	$ 224.8	$ 213.4
Deferred Revenue	7.6	5.4
Unbilled receivables	1.9	2.3
Total customer receivables	226.7	215.7
Accounts Receivable, Allowance for Credit Loss, Current	4.5	3.5
Receivables, Net, Current	$ 222.2	$ 212.2

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	$ 4.7		$ 4.7		$ 4.8
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	21.00%	21.00%
State income taxes, net of federal benefit	3.60%	4.20%	3.60%	4.20%
Tax benefits from stock compensation	0.00%	(0.30%)	(0.20%)	(0.20%)
Tax credits	(1.30%)	(1.10%)	(1.30%)	(1.10%)
Other	0.70%	2.10%	0.90%	1.70%

Income Taxes Income Tax Rate Re

Income Taxes Income Tax Rate Reconciliation (Details)	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	21.00%	21.00%
Adjustments to reconcile to the effective tax rate:
State income taxes, net of federal benefit	3.60%	4.20%	3.60%	4.20%
Valuation allowance adjustment related to stock compensation	(0.30%)	(0.60%)	0.20%	(0.20%)
Tax benefits from stock compensation	0.00%	(0.30%)	(0.20%)	(0.20%)
Tax credits	(1.30%)	(1.10%)	(1.30%)	(1.10%)
Effective Income Tax Rate Reconciliation, GILTI, percent	0.80%	0.60%	0.80%	0.60%
Other	0.70%	2.10%	0.90%	1.70%
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent	(1.40%)	(0.30%)	(1.40%)	(0.30%)

Borrowing Arrangements (Narrati

Borrowing Arrangements (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2020	Jun. 12, 2018
Outstanding letter of credit accrued fees and expenses		$ 0.2
Cash and cash equivalents			$ 228.2	$ 208.9
Future maturities of outstanding borrowings
Outstanding letters of credit		14.7
Domestic Line of Credit [Member]
Revolving credit facility amount		$ (175)
Line of Credit Facility, Interest Rate at Period End		200.00%
Future maturities of outstanding borrowings
Line of Credit Facility, Maximum Borrowing Capacity		$ 175
Potential increase size of the credit facility by an additional amount		150
Unsecured Debt [Member]
Long-term Debt, Gross					$ 450
Future maturities of outstanding borrowings
Payments of debt issuance costs	$ 5.5
Swing Line Loans [Member]
Revolving credit facility amount		(25)
Future maturities of outstanding borrowings
Line of Credit Facility, Maximum Borrowing Capacity		25
Letters Of Credit Outstanding [Member]
Revolving credit facility amount		(60)
Future maturities of outstanding borrowings
Line of Credit Facility, Maximum Borrowing Capacity		$ 60
5.5% Senior Notes
Debt Instrument, Interest Rate, Effective Percentage		4.00%
Future maturities of outstanding borrowings
Financial Liabilities Fair Value Disclosure		$ 426
Minimum [Member] | Domestic Line of Credit [Member]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage		37.50%
London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member] | Long-term Debt [Member]
Debt Instrument, Basis Spread on Variable Rate		100.00%
London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member] | Domestic Line of Credit [Member]
Debt Instrument, Basis Spread on Variable Rate		200.00%
London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member] | Domestic Line of Credit [Member]
Debt Instrument, Basis Spread on Variable Rate		225.00%
Base Rate [Member] | Maximum [Member] | Domestic Line of Credit [Member]
Debt Instrument, Basis Spread on Variable Rate		125.00%

Borrowing Arrangements (Compone

Borrowing Arrangements (Components Of Long-Term Debt) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021
Debt instrument	$ 452.1	$ 452.2
Deferred financing costs	(5)	(5.3)
Current portion of long-term debt	(1)	(1)
Long-term debt	446.1	445.9
Unsecured Debt [Member]
5.5% Senior Notes	450	450
Other [Member]
Debt instrument	$ 2.1	$ 2.2

Derivative Financial Instrume_2

Derivative Financial Instruments (Details) $ in Millions	Sep. 30, 2021USD ($)
Foreign Exchange Contract [Member]
Derivative [Line Items]
Other noncurrent liabilities	$ 1.1

Retirement Plans (Net Periodic

Retirement Plans (Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Defined Benefit Plan, Service Cost	$ 0.3	$ 0.4	$ 0.6	$ 0.8
Defined Benefit Plan, Interest Cost	2.4	2.5	4.8	5
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(3.8)	(3.9)	(7.6)	(7.8)
Amortization of actuarial net loss	0.4	0.6	0.8	1.2
Defined Benefit Plan, Net Periodic Benefit Cost other than Service Cost	(1)	(0.8)	(2)	(1.6)
Net periodic benefit cost	$ (0.7)	$ (0.4)	$ (1.4)	$ (0.8)

Stock-based Compensation Plan_2

Stock-based Compensation Plans (Narrative) (Details) $ / shares in Units, $ in Millions	Nov. 30, 2021	Mar. 31, 2022USD ($)$ / sharesshares	Dec. 31, 2021$ / sharesshares	Mar. 31, 2021shares	Mar. 31, 2022USD ($)$ / sharesshares
Share-based Payment Arrangement, Expense | $		$ 2.5
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $		$ 13.3			$ 13.3
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		944,631		664,082
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	1.70%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	0.76%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	2 years 9 months 29 days
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	1.70%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	0.76%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	2 years 9 months 29 days
Phantom Share Units (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instrument Other than Option, Nonvested, Intrinsic Value | $ / shares		$ 12.92			$ 12.92
Share-based compensation liability | $		$ 2.1			$ 2.1
Granted, shares			199,549
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares			$ 13.64
Granted, shares			199,549
Performance Shares [Member]
Share-based compensation, units awarded but not yet granted		58,139			58,139
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period		104,380
Granted, shares		88,250	135,129
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares		$ 13.03	$ 13.64
Granted, shares		88,250	135,129
Market Based Performance Shares
Granted, shares			230,089
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares			$ 15.76
Granted, shares			230,089
Equity Option
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	1.62%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	1.33%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	6 years
Granted, shares			457,482
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	1.62%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares			$ 3.43
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	1.33%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	6 years
Granted, shares			457,482
Minimum [Member] | Performance Shares [Member]
Performance Factors					0
Minimum [Member] | Market Based Performance Shares
Performance Factors					0
Maximum [Member] | Performance Shares [Member]
Performance Factors					2
Maximum [Member] | Market Based Performance Shares
Performance Factors					2
Share-based Payment Arrangement, Tranche Two [Member] | Performance Shares [Member]
Granted, shares			57,627
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares			$ 13.81
Granted, shares			57,627

Stock-based Compensation Plan_3

Stock-based Compensation Plans Grants Table (Details) - USD ($) $ / shares in Units, $ in Thousands	Nov. 30, 2021	Mar. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Granted, Value, Share-based Payment Arrangement, before Forfeiture		$ 11,800
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	1.70%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	0.76%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	2 years 9 months 29 days
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares		88,250	135,129
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 13.03	$ 13.64
Shares Granted, Value, Share-based Payment Arrangement, before Forfeiture		$ 1,100	$ 1,800
Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares		38,512	38,069
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 3.39	$ 3.01
Shares Granted, Value, Share-based Payment Arrangement, before Forfeiture		$ 100	$ 100
Phantom Share Units (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares			199,549
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 13.64
Shares Granted, Value, Share-based Payment Arrangement, before Forfeiture			$ 2,700
Market Based Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares			230,089
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 15.76
Shares Granted, Value, Share-based Payment Arrangement, before Forfeiture			$ 3,600
Equity Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares			457,482
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 3.43
Shares Granted, Value, Share-based Payment Arrangement, before Forfeiture			$ 1,600
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	1.62%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	1.33%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	6 years
Share-based Payment Arrangement, Tranche Two [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares			57,627
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 13.81
Shares Granted, Value, Share-based Payment Arrangement, before Forfeiture			$ 800

Supplemental Balance Sheet In_3

Supplemental Balance Sheet Information (Schedule Of Selected Supplemental Balance Sheet Information) (Details) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2022	Sep. 30, 2021
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 164.1	$ 227.5
Inventories:
Purchased components and raw material	137.4	100.9
Work in process	46.4	41.6
Finished goods	45.4	42.2
Inventories, net	229.2	184.7
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid Expense	13.1	12.8
Nontrade Receivables	10.7	10.7
Maintenance and repair tooling	2.3	2.9
Income taxes	0.2	0.2
Other Receivables	1.7	0.8
Other	3.6	1.9
Other	31.6	29.3
Property, plant and equipment:
Land	5.5	6.1
Buildings	86.7	84.6
Machinery and equipment	446.1	433.3
Construction in progress	93	83.7
Property, plant and equipment, gross	631.3	607.7
Accumulated depreciation	(339)	(324.3)
Property, plant and equipment net	292.3	283.4
Other Assets, Noncurrent [Abstract]
Operating lease, Right-of-Use asset	25.7	27.1
us-Maintenance, repair and tooling supplies	20.5	19.3
Nontrade Receivables, Noncurrent	5	2.7
Assets for Plan Benefits, Defined Benefit Plan	19	16.8
Notes Receivable, Related Parties, Noncurrent	1.8	1.8
Debt Issuance Costs, Noncurrent, Net	1.1	1.3
Other Assets, Miscellaneous, Noncurrent	3.8	4.3
Other noncurrent assets	76.9	73.3
Goodwill, Foreign Currency Translation Gain (Loss)	0.6
Goodwill	115.8	$ 115.1
Goodwill, Acquired During Period	$ 0.1

Schedule of Accrued Liabilities

Schedule of Accrued Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021
Other current liabilities:
Compensation and benefits	$ 32.4	$ 44.6
Customer rebates	7.7	19.6
Warranty	5.9	6.7
Deferred Revenue	7.6	5.4
Customer Refund Liability, Current	5.2	6
Accrual for Taxes Other than Income Taxes	5.5	4.4
Operating lease liability, current	3.8	4
Estimated Litigation Liability, Current	3.1	2.6
CARES Act deferral, current portion	3.6	3.6
Restructuring reserve, current	2.1	3.1
Environmental	1.2	1.2
Interest Payable	5.3	6.2
Accrued Income Taxes	1.7	8.5
Other Liabilities, Current	7.4	11.2
Accrued liabilities	92.5	127.1
Other Liabilities, Noncurrent [Abstract]
Operating lease liability, noncurrent	23	24.6
Standard Product Warranty Accrual, Noncurrent	1.7	3
CARES Act Deferrals	0	3.6
Transition Tax Liability	4.1	4.7
Unrecognized Tax Benefits	4.7	4.8
New market tax credit liabilities	3.9	3.9
Workers' Compensation Liability, Noncurrent	10.6	7.9
Asset Retirement Obligation	3.6	3.6
Grant yet to be earned	2.5	2.5
Other Accrued Liabilities, Noncurrent	3	3.4
Other Liabilities, Noncurrent, Total	$ 57.1	$ 62

Segment Information (Narrative)

Segment Information (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Restructuring and other charges	$ (0.6)	$ (0.8)	$ (3)	$ (2.2)
Operating income	34.2	33.4	63.1	61.2
Depreciation, Depletion and Amortization	14.8	14.7	30	29.4
Payments to Acquire Productive Assets	15	15.5	26	31.1
Net sales	310.5	267.5	582.8	504.9
Mueller Co. [Member]
Segment Reporting Information [Line Items]
Restructuring and other charges	0	0	0	(0.1)
Operating income	35.4	29.7	66.7	52.8
Depreciation, Depletion and Amortization	7.5	7.5	14.9	14.9
Payments to Acquire Productive Assets	12.1	13.8	21.5	26.1
Net sales	183.9	147.1	338.8	275.9
Mueller Co. [Member] | Central Region [Member]
Segment Reporting Information [Line Items]
Net sales	50.7	38.4	91.2	73.4
Mueller Co. [Member] | Northeast Region [Member] [Member]
Segment Reporting Information [Line Items]
Net sales	31.1	22.4	61.1	47.3
Mueller Co. [Member] | Southeast Region [Member]
Segment Reporting Information [Line Items]
Net sales	40.7	29.9	78	53
Mueller Co. [Member] | Western Region [Member]
Segment Reporting Information [Line Items]
Net sales	45.8	43.4	83.9	79.7
Mueller Co. [Member] | UNITED STATES
Segment Reporting Information [Line Items]
Net sales	168.3	134.1	314.2	253.4
Mueller Co. [Member] | CANADA
Segment Reporting Information [Line Items]
Net sales	14	11.1	21.9	16.8
Mueller Co. [Member] | Other International Locations [Member]
Segment Reporting Information [Line Items]
Net sales	1.6	1.9	2.7	5.7
Corporate
Segment Reporting Information [Line Items]
Restructuring and other charges	(0.5)	(1.5)	(2.9)	(2.8)
Operating income	(12.9)	(14.6)	(26.8)	(26.9)
Depreciation, Depletion and Amortization	0	0	0.1	0.1
Payments to Acquire Productive Assets	0	0	0	0.1
Mueller Technologies [Member]
Segment Reporting Information [Line Items]
Restructuring and other charges	(0.1)	(0.7)	(0.1)	(0.7)
Operating income	11.7	18.3	23.2	35.3
Depreciation, Depletion and Amortization	7.3	7.2	15	14.4
Payments to Acquire Productive Assets	2.9	1.7	4.5	4.9
Net sales	126.6	120.4	244	229
Mueller Technologies [Member] | Central Region [Member]
Segment Reporting Information [Line Items]
Net sales	34.6	32.3	63.4	59.2
Mueller Technologies [Member] | Northeast Region [Member] [Member]
Segment Reporting Information [Line Items]
Net sales	28.4	24.2	52.7	48.6
Mueller Technologies [Member] | Southeast Region [Member]
Segment Reporting Information [Line Items]
Net sales	26.3	24.7	51.8	47.5
Mueller Technologies [Member] | Western Region [Member]
Segment Reporting Information [Line Items]
Net sales	22.3	23.1	47	45.2
Mueller Technologies [Member] | UNITED STATES
Segment Reporting Information [Line Items]
Net sales	111.6	104.3	214.9	200.5
Mueller Technologies [Member] | CANADA
Segment Reporting Information [Line Items]
Net sales	8.7	9.4	16.3	16.1
Mueller Technologies [Member] | Other International Locations [Member]
Segment Reporting Information [Line Items]
Net sales	$ 6.3	$ 6.7	$ 12.8	$ 12.4

Segment Information (Schedule O

Segment Information (Schedule Of Selected Supplemental Balance Sheet Information) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Segment Reporting Information [Line Items]
Net sales	$ 310.5	$ 267.5	$ 582.8	$ 504.9
Operating income	34.2	33.4	63.1	61.2
Depreciation and amortization	14.8	14.7	30	29.4
Restructuring and other charges	0.6	0.8	3	2.2
Payments to Acquire Productive Assets	15	15.5	26	31.1
Total assets	1,511.5		1,511.5		$ 1,518
Intangible intangible assets, net	379.4		379.4		$ 392.5
Mueller Co. [Member]
Segment Reporting Information [Line Items]
Net sales	183.9	147.1	338.8	275.9
Operating income	35.4	29.7	66.7	52.8
Depreciation and amortization	7.5	7.5	14.9	14.9
Restructuring and other charges	0	0	0	0.1
Payments to Acquire Productive Assets	12.1	13.8	21.5	26.1
Mueller Co. [Member] | Central Region [Member]
Segment Reporting Information [Line Items]
Net sales	50.7	38.4	91.2	73.4
Mueller Co. [Member] | Northeast Region [Member] [Member]
Segment Reporting Information [Line Items]
Net sales	31.1	22.4	61.1	47.3
Mueller Co. [Member] | Southeast Region [Member]
Segment Reporting Information [Line Items]
Net sales	40.7	29.9	78	53
Mueller Co. [Member] | Western Region [Member]
Segment Reporting Information [Line Items]
Net sales	45.8	43.4	83.9	79.7
Mueller Co. [Member] | CANADA
Segment Reporting Information [Line Items]
Net sales	14	11.1	21.9	16.8
Mueller Co. [Member] | Other International Locations [Member]
Segment Reporting Information [Line Items]
Net sales	1.6	1.9	2.7	5.7
Mueller Co. [Member] | UNITED STATES
Segment Reporting Information [Line Items]
Net sales	168.3	134.1	314.2	253.4
Mueller Technologies [Member]
Segment Reporting Information [Line Items]
Net sales	126.6	120.4	244	229
Operating income	11.7	18.3	23.2	35.3
Depreciation and amortization	7.3	7.2	15	14.4
Restructuring and other charges	0.1	0.7	0.1	0.7
Payments to Acquire Productive Assets	2.9	1.7	4.5	4.9
Mueller Technologies [Member] | Central Region [Member]
Segment Reporting Information [Line Items]
Net sales	34.6	32.3	63.4	59.2
Mueller Technologies [Member] | Northeast Region [Member] [Member]
Segment Reporting Information [Line Items]
Net sales	28.4	24.2	52.7	48.6
Mueller Technologies [Member] | Southeast Region [Member]
Segment Reporting Information [Line Items]
Net sales	26.3	24.7	51.8	47.5
Mueller Technologies [Member] | Western Region [Member]
Segment Reporting Information [Line Items]
Net sales	22.3	23.1	47	45.2
Mueller Technologies [Member] | CANADA
Segment Reporting Information [Line Items]
Net sales	8.7	9.4	16.3	16.1
Mueller Technologies [Member] | Other International Locations [Member]
Segment Reporting Information [Line Items]
Net sales	6.3	6.7	12.8	12.4
Mueller Technologies [Member] | UNITED STATES
Segment Reporting Information [Line Items]
Net sales	$ 111.6	$ 104.3	$ 214.9	$ 200.5

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	12 Months Ended
	Sep. 30, 2012CAD ($)
Loss Contingency, Damages Sought, Value	$ 10

Subsequent Events (Details)

Subsequent Events (Details) - $ / shares	May 20, 2022	May 10, 2022	Apr. 22, 2022	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Subsequent Event [Line Items]
Dividends declared per share, in dollars per share				$ 0.058	$ 0.055	$ 0.116	$ 0.110
Subsequent Event [Member]
Subsequent Event [Line Items]
Dividends Payable, Date Declared			Apr. 22, 2022
Dividends declared per share, in dollars per share			$ 0.058
Dividends Payable, Date to be Paid	May 20, 2022
Dividends Payable, Date of Record		May 10, 2022

Business Combinations and Ass_3

Business Combinations and Asset Acquisitions (Details)	3 Months Ended
	Mar. 31, 2022USD ($)
Acquistions [Abstract]
Payments to Acquire Businesses, Net of Cash Acquired	$ 19.7
Receivables	500,000
Inventories	600,000
Other current assets	900,000
Indefinite-lived Intangible Assets Acquired	1,800,000
Goodwill	12,100,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable	(800,000)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	(1,300,000)
Consideration paid considered as cash flow used in financing	19,500,000
Other Payments to Acquire Businesses	19.5
Customer-Related Intangible Assets [Member]
Acquistions [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	2,100,000
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	2,100,000
Noncompete Agreements
Acquistions [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	100,000
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	100,000
Developed Technology Rights
Acquistions [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	3,500,000
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 3,500,000