[CAL LOGO OMITTED]                  NEWS RELEASE
                          CALIFORNIA WATER SERVICE GROUP       [GRAPHIC OMITTED]


             1720 North First Street
             San Jose, CA 95112-4598                             July 27, 2005


Contact:     Richard D. Nye (408) 367-8216 (analysts)
             Shannon Dean   (310) 257-1435 (media)


                CAL WATER ANNOUNCES SECOND QUARTER 2005 RESULTS;
               BOARD DECLARES 243rd CONSECUTIVE QUARTERLY DIVIDEND
          AND APPOINTS NEW VICE PRESIDENT, ENGINEERING & WATER QUALITY
- --------------------------------------------------------------------------------

SAN JOSE, CA - California Water Service Group (NYSE : CWT) today announced net
income of $7.6 million and earnings of $0.41 per share for the second quarter of
2005, compared to net income of $10.1 million and earnings of $0.59 per share in
the second quarter of 2004.

     Revenue for the second  quarter  decreased  $7.4  million,  or 8%, to $81.5
million. Rate increases added $2.5 million to revenue and sales to new customers
added $0.9 million.  These increases were offset by a $10.8 million  decrease in
sales to existing customers  resulting from cooler  temperatures and higher than
normal rainfall.

     "Our results  continue to be hampered by cool weather and an unusual amount
of  precipitation.  In  California,  we had 2.5  inches  of  rain in the  second
quarter,  compared to less than  one-third  of an inch in the second  quarter of
2004.  Long  term,  the  above-average  precipitation  replenishes  the  state's
underground  aquifers and reservoirs;  in the short term,  however, it decreases
sales and impacts our  earnings,"  said  President and Chief  Executive  Officer
Peter C. Nelson.

                                                                               5



     "Despite  the rain,  we continue to execute  our  strategy by  aggressively
pursuing fair regulatory treatment, operating efficiently, adding customers, and
providing  excellent  service,  and we expect to see  improved  results when the
weather heats up and sales rise," Nelson said.

     Total  operating  expenses  for the second  quarter  decreased  6%, or $4.6
million.  Water  production  costs  decreased  12% due to the  decrease in water
usage. Other operations expenses were comparable to those incurred in the second
quarter of 2004.  Maintenance  expense  increased 24%,  reflecting  work done on
wells,  pumping  equipment,  water  treatment  equipment,   mains,  and  meters.
Depreciation expense increased 7% due to increases in 2004 capital expenditures.
Income taxes were 25% lower due to lower pre-tax income.

     Other income increased $0.2 million, or 34%, primarily due to interest from
short term investments.  There were minimal gains from property sales for either
quarter.

     On July  21,  2005,  the  California  Public  Utilities  Commission  (CPUC)
approved the Company's 2004 General Rate Case filing (GRC),  which will increase
revenues by $7.6 million on an annual basis. The decision is  substantially  the
same as the proposed decision  announced on June 28, 2005. The GRC includes 8 of
the Company's 24 districts and nearly 50% of the Company's California customers.
The new rates were effective July 26, 2005.

     At their meeting today,  Directors declared the 243rd consecutive quarterly
dividend on common  stock in the amount of $0.2850.  It is payable on August 19,
2005,  to  stockholders  of record on August 8, 2005.  The  regular  dividend on
Series C preferred stock was also declared.

     The Board also appointed Michael J. Rossi as Vice President,  Engineering &
Water Quality,  effective  October 1, 2005.  Currently  California Water Service
Company's  Chief  Engineer,  Rossi began his career with the Company in 1977. He

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holds a Bachelor of Science Degree in Civil  Engineering and a Master of Science
Degree in Business Administration,  both earned at San Jose State University. He
is also a registered  civil  engineer and  state-certified  water  treatment and
water distribution operator.

     Robert R. Guzzetta, who currently holds the position, was appointed as Vice
President  of  Operations.  He will succeed  Raymond H. Taylor,  who is retiring
after 23 years of service.

     At the same time, the Board approved additional changes in responsibilities
of three other officers of the Company. Dan L. Stockton,  current Vice President
of Information  Systems, was appointed Vice President,  Corporate  Development &
Corporate Secretary; Paul G. Ekstrom, currently Vice President, Customer Service
&  Corporate  Secretary,  was  appointed  Vice  President,  Customer  Service  &
Information  Systems;   and  Francis  S.  Ferraro,   currently  Vice  President,
Regulatory  Matters &  Corporate  Development,  was  appointed  Vice  President,
Regulatory & Corporate Relations. All changes will be effective October 1, 2005.

         "These key leadership changes further position the Company to achieve
its objectives," Nelson said.

         Investors are invited to listen to the Company's analyst
teleconference, which is scheduled for 4:00 p.m. EDT / 1:00 p.m. PDT on July 28,
2005. The call-in number is 1-866-814-1919 and the ID No. is 733669. A replay is
available through September 25, 2005, by calling 1-888-266-2081 and entering
pass code 733669.

     California  Water Service Group is the parent  company of California  Water
Service  Company,  Washington  Water Service  Company,  New Mexico Water Service
Company, Hawaii Water Service Company, Inc., and CWS Utility Services.  Together
these companies provide regulated and non-regulated water service to more than 2
million  people  in  100  California,   Washington,   New  Mexico,   and  Hawaii
communities.

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Group's  common  stock  trades on the New York Stock  Exchange  under the symbol
"CWT."

     This news release contains  forward-looking  statements  within the meaning
established by the Private Securities Litigation Reform Act of 1995 ("Act"). The
forward-looking  statements  are  intended to qualify  under  provisions  of the
federal  securities  laws for "safe harbor"  treatment  established  by the Act.
Forward-looking   statements  are  based  on  currently  available  information,
expectations,  estimates, assumptions and projections, and management's judgment
about the Company,  the water utility industry and general economic  conditions.
Such  words  as  expects,   intends,   plans,  believes,   estimates,   assumes,
anticipates,  projects,  predicts,  forecasts  or  variations  of such  words or
similar  expressions are intended to identify  forward-looking  statements.  The
forward-looking  statements are not guarantees of future  performance.  They are
subject to  uncertainty  and changes in  circumstances.  Actual results may vary
materially from what is contained in a forward-looking  statement.  Factors that
may cause a result different than expected or anticipated include:  governmental
and regulatory commissions' decisions, including decisions on proper disposition
of property;  changes in regulatory  commissions'  policies and procedures;  the
timeliness  of  regulatory  commissions'  actions  concerning  rate relief;  new
legislation;  the ability to satisfy  requirements related to the Sarbanes-Oxley
Act and other regulations on internal  controls;  electric power  interruptions;
increases in suppliers' prices and the availability of supplies  including water
and power;  fluctuations in interest rates; changes in environmental  compliance
and water quality  requirements;  acquisitions  and our ability to  successfully
integrate  acquired  companies;  the ability to successfully  implement business
plans;  changes in customer  water use patterns;  the impact of weather on water
sales and operating results; access to sufficient capital on satisfactory terms;
civil  disturbances  or terrorist  threats or acts,  or  apprehension  about the
possible future  occurrences of acts of this type; the involvement of the United
States in war or other hostilities;  restrictive  covenants in or changes to the
credit  ratings on our current or future debt that could  increase our financing
costs or affect our ability to borrow,  make payments on debt or pay  dividends;
and,  other  risks  and  unforeseen  events.  When  considering  forward-looking
statements,  you should keep in mind the cautionary  statements included in this
paragraph.  The  Company  assumes no  obligation  to provide  public  updates of
forward-looking statements.

   Additional information is available at our Web site at www.calwatergroup.com.

   Attachments (2).

                                       ###

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CALIFORNIA WATER SERVICE GROUP
CONDENSED CONSOLIDATED BALANCE SHEETS
Unaudited
(In thousands, except per share data)                                  June 30,     December 31,
                                                                         2005           2004
                                                                     -----------    ------------
ASSETS
Utility plant:
                                                                              
         Utility plant                                               $ 1,177,272    $ 1,144,074
         Less accumulated depreciation and amortization                  358,184        343,769
                                                                     -----------    -----------
                                                                         819,088        800,305
                                                                     -----------    -----------
Current assets:
         Cash and cash equivalents                                        19,243         18,820
         Receivables, net of allowances for uncollectible accounts
           of $286 at June 30, 2005 and $ 287 at December 31, 2004
                     Customers                                            18,331         15,867
                     Income taxes                                            363          7,298
                     Other                                                 4,629          3,147
         Unbilled revenue                                                 13,601          9,307
         Materials and supplies, at average cost                           3,834          3,161
         Prepaid pension expense                                             281          3,671
         Taxes and other prepaid expenses                                  5,501          9,122
                                                                     -----------    -----------
                                     Total current assets                 65,783         70,393
                                                                     -----------    -----------
Regulatory assets                                                         55,174         53,477
Other assets                                                              19,646         18,678
                                                                     -----------    -----------
                                                                     $   959,691    $   942,853
                                                                     ===========    ===========
CAPITALIZATION AND LIABILITIES
Capitalization:
         Common stock, $.01 par value                                $       184    $       184
         Additional paid-in capital                                      131,510        131,271
         Retained earnings                                               154,574        156,851
         Accumulated other comprehensive loss                               (701)          (701)
                                                                     -----------    -----------
                Total common stockholders' equity                        285,567        287,605
         Preferred stock                                                   3,475          3,475
         Long-term debt, less current maturities                         274,538        274,821
                                                                     -----------    -----------
                Total capitalization                                     563,580        565,901
                                                                     -----------    -----------
Current liabilities:
         Current maturities of long-term debt                              1,144          1,100
         Short-term borrowings                                                --             --
         Accounts payable                                                 30,096         19,745
         Accrued expenses and other liabilities                           37,868         36,367
                                                                     -----------    -----------
                Total current liabilities                                 69,108         57,212

Unamortized investment tax credits                                         2,721          2,721
Deferred income taxes                                                     56,710         54,826
Regulatory and other liabilities                                          36,170         35,986
Advances for construction                                                136,010        131,292
Contributions in aid of construction                                      95,392         94,915
Commitments and contingencies                                                 --             --
                                                                     -----------    -----------
                                                                     $   959,691    $   942,853
                                                                     ===========    ===========

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CALIFORNIA WATER SERVICE GROUP
CONDENSED CONSOLIDATED STATEMENTS OF INCOME
(In thousands, except per share data)
Unaudited
                                            For the three months ended:   For the six months ended:
                                               June 30,   June 30,           June 30,   June 30,
                                                 2005       2004               2005       2004
                                               --------   --------           --------   --------
                                                                            
Operating revenue                              $ 81,457   $ 88,845           $141,760   $149,085
                                               --------   --------           --------   --------
Operating expenses:
     Water production costs                      29,395     33,563             49,215     54,724
     Other operations                            21,804     21,887             43,747     42,224
     Maintenance                                  3,759      3,032              7,418      6,213
     Depreciation and amortization                7,006      6,521             14,002     13,039
     Income taxes                                 5,148      6,844              5,603      7,802
     Property and other taxes                     3,092      2,915              6,057      5,609
                                               --------   --------           --------   --------
        Total operating expenses                 70,204     74,762            126,042    129,611
                                               --------   --------           --------   --------

        Net operating income                     11,253     14,083             15,718     19,474
                                               --------   --------           --------   --------
Other income and expenses:
        Non-regulated income, net                   705        573              1,343      1,123
        Gain on sale of non-utility property         61         --                 59          1
                                               --------   --------           --------   --------
        Total other income and expenses             766        573              1,402      1,124
                                               --------   --------           --------   --------

Interest expense:
     Interest expense                             4,653      4,752              9,299      9,398
     Less capitalized interest                      225        150                450        300
                                               --------   --------           --------   --------
        Total interest expense                    4,428      4,602              8,849      9,098
                                               --------   --------           --------   --------

Net income                                     $  7,591   $ 10,054           $  8,271   $ 11,500
                                               ========   ========           ========   ========
Earnings per share
     Basic                                     $   0.41   $   0.59           $   0.45   $   0.67
                                               ========   ========           ========   ========
     Diluted                                   $   0.41   $   0.59           $   0.45   $   0.67
                                               ========   ========           ========   ========
Weighted average shares outstanding
     Basic                                       18,373     16,965             18,372     16,949
                                               ========   ========           ========   ========
     Diluted                                     18,407     16,983             18,404     16,967
                                               ========   ========           ========   ========
Dividends per share of common stock            $ 0.2850   $ 0.2825           $ 0.5700   $ 0.5650
                                               ========   ========           ========   ========


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