Exhibit 99.1

		1720 North First Street		October 31, 2007
		San Jose, CA 95112-4598		For Immediate Release
Contact:		Marty Kropelnicki (408) 367-8200 (analysts)
		Shannon Dean (310) 257-1435 (media)

CAL WATER REPORTS THIRD QUARTER 2007 RESULTS AND
ANNOUNCES 252^ND CONSECUTIVE QUARTERLY DIVIDEND

     SAN JOSE, CA — California Water Service Group (NYSE : CWT) today announced net income of $13.8 million and earnings per common share of $0.67 for the third quarter of 2007, compared to net income of $12.6 million and earnings of $0.68 per common share in the third quarter of 2006. Earnings per share decreased in the third quarter of 2007 by approximately $0.08 per common share on a diluted basis as a result of the equity offering completed in October 2006.

     Revenues increased by $6.1 million, or 6%, to $113.9 million, compared to the same quarter of 2006, benefiting from a $5.1 million increase in rates, a $0.8 million increase in sales to new customers, and a $0.2 million increase in water sales to existing customers.

     Total operating expenses for the third quarter of 2007 increased by $4.6 million, or 5%, to $96.3 million compared to the same quarter of 2006. Other operations expenses increased $2.7 million, or 12%, to $26.5 million compared to the same period last year. Contributing to this amount were increases in outside services, such as legal and consulting fees and employee benefit programs (medical and pension benefit costs).

     Maintenance expenses were $4.2 million, unchanged from the same period last year. Depreciation expense increased $0.7 million, or 9%, to $8.4 million due to 2006 capital expenditures, compared to the third quarter of 2006. Taxes other than income

taxes increased $0.2 million, or 7%, to $3.7 million. Total income taxes remained the same as last year and net other income increased approximately $0.3 million.

     “Typically, our third quarter financial performance benefits from higher water sales due to the warmer weather, but this year we experienced milder summer weather throughout much of California. Customers also have heeded public calls for water conservation within the state and, as a result, we noticed very minor increases in demand by existing customers,” said President and Chief Executive Officer Peter C. Nelson.

     “Additionally, although we are currently collecting interim rates associated with our 2006 General Rate Case, they are below what we requested in the rate case proceeding before the Commission. The results of our 2006 GRC are pending final approval from the California Public Utilities Commission and, once approved, we will be able to collect the difference between the interim rates and the final rates approved,” Nelson said.

Year-to-Date Results

     For the nine months ended September 30, 2007, net income increased $4.0 million, or 21%, to $23.1 million, compared to $19.2 million for the same period in the previous year. Earnings per share increased $0.08, or 8%, to $1.11, compared to $1.03 for the same period in 2006. Revenues for the nine months increased $27.1 million, or 11%, to $281.2 million, compared to $254.1 million for the same period in the previous year. The equity offering completed in October 2006 decreased earnings per share by approximately $0.14 per common share on a diluted basis for the nine months ended September 30, 2007.

     Nelson said that in the fourth quarter, the Company intends to remain focused on working with the Commission to implement the Water Action Plan and finalizing the 2006 General Rate Case.

     “Going forward, we will continue to manage expenses, pursue strategic growth opportunities, and work on innovative regulatory solutions that benefit our stockholders, customers, and employees,” he said.

Dividend Declaration

     At their meeting on October 24, 2007, the Directors of California Water Service Group declared the 252^nd consecutive quarterly dividend on common stock. The quarterly dividend of $0.29 per share will be payable on November 16, 2007, to stockholders of record on November 5, 2007. The Board also declared a regular dividend on Series C preferred stock.

Quarterly Earnings Call Information

      All stockholders and interested investors are invited to listen to the 2007 third quarter conference call on November 1, 2007, at 11:00 a.m. (EDT), by dialing 1-866-225-2976 and keying in ID# 1143157. A replay of the call will be available from 2:00 p.m. (EDT) on November 1, 2007, through December 31, 2007, at 888-266-2081, ID# 1143157. The call, which will be hosted by President and Chief Executive Officer Peter C. Nelson and Vice President and Chief Financial Officer Martin A. Kropelnicki, will also be webcast under the investor relations tab at www.calwatergroup.com.

     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 nearly 2 million people in 100 California, Washington, New Mexico, and Hawaii communities. The 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

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

###

CALIFORNIA WATER SERVICE GROUP
CONDENSED CONSOLIDATED BALANCE SHEETS
Unaudited
(In thousands, except per share data)

		September 30				December 31
		2007				2006
ASSETS
Utility plant:
Utility plant		$	1,420,585			$	1,344,415
Less accumulated depreciation and amortization			(429,319	)			(402,940	)
Net utility plant			991,266				941,475
Current assets:
Cash and cash equivalents			26,491				60,312
Receivables
Customers			29,514				19,526
Other			7,549				6,700
Unbilled revenue			14,711				11,341
Materials and supplies at average cost			4,789				4,515
Prepaid pension expense			—				1,696
Taxes and other prepaid expenses			5,300				5,534
Total current assets			88,354				109,624
Other assets:
Regulatory assets			93,907				93,785
Other assets			22,377				20,135
Total other assets			116,284				113,920
		$	1,195,904			$	1,165,019
CAPITALIZATION AND LIABILITIES
Capitalization:
Common stock, $.01 par value		$	207			$	207
Additional paid-in capital			211,782				211,513
Retained earnings			171,607				166,582
Total common stockholders’ equity			383,596				378,302
Preferred stock			3,475				3,475
Long-term debt, less current maturities			291,051				291,814
Total capitalization			678,122				673,591
Current liabilities:
Current maturities of long-term debt			1,832				1,778
Accounts payable			39,086				33,130
Accrued expenses and other liabilities			40,747				35,317
Total current liabilities			81,665				70,225
Unamortized investment tax credits			2,541				2,541
Deferred income taxes, net			69,517				69,503
Pension and postretirement benefits other than pensions			48,584				48,584
Regulatory and other liabilities			33,724				33,411
Advances for construction			167,719				157,660
Contributions in aid of construction			114,032				109,504
Commitments and contingencies
		$	1,195,904			$	1,165,019

CALIFORNIA WATER SERVICE GROUP
CONDENSED CONSOLIDATED STATEMENTS OF INCOME
Unaudited
(In thousands, except per share data)

		For the three months ended:
		September 30, 2007
		2007				2006
Operating revenue		$	113,851			$	107,755
Operating expenses:
Water production costs			45,063				43,998
Other operations			26,495				23,756
Maintenance			4,233				4,173
Depreciation and amortization			8,392				7,717
Income taxes			8,426				8,552
Property and other taxes			3,707				3,477
Total operating expenses			96,316				91,673
Net operating income			17,535				16,082
Other income and expenses:
Non-regulated revenue			3,418				2,358
Non-regulated expenses			(2,136	)			(1,610	)
Gain on sale of non-utility property			—				—
Less: income taxes on other income and expenses			(522	)			(305	)
			760				443
Interest expense:
Interest Expense			4,936				5,031
Less: capitalized interest			(450	)			(1,125	)
Net interest expense			4,486				3,906
Net income		$	13,809			$	12,619
Earnings per share
Basic		$	0.67			$	0.68
Diluted		$	0.67			$	0.68
Weighted average shares outstanding
Basic			20,667				18,407
Diluted			20,691				18,424
Dividends per share of common stock		$	0.2900			$	0.2875

CALIFORNIA WATER SERVICE GROUP
CONDENSED CONSOLIDATED STATEMENTS OF INCOME
Unaudited
(In thousands, except per share data)

		For the nine months ended:
		September 30, 2007
		2007				2006
Operating revenue		$	281,203			$	254,072
Operating expenses:
Water production costs			108,147				95,637
Other operations			75,425				70,943
Maintenance			13,983				11,503
Depreciation and amortization			25,173				23,066
Income taxes			13,761				12,593
Property and other taxes			10,548				9,698
Total operating expenses			247,037				223,440
Net operating income			34,166				30,632
Other income and expenses:
Non-regulated revenue			9,883				6,713
Non-regulated expenses			(5,853	)			(4,948	)
Gain on sale of non-utility property			(83	)			348
Less: income taxes on other income and expenses			(1,608	)			(861	)
			2,339				1,252
Interest expense:
Interest Expense			14,788				14,698
Less: capitalized interest			(1,400	)			(1,975	)
Net interest expense			13,388				12,723
Net income		$	23,117			$	19,161
Earnings per share
Basic		$	1.11			$	1.03
Diluted		$	1.11			$	1.03
Weighted average shares outstanding
Basic			20,664				18,405
Diluted			20,688				18,426
Dividends per share of common stock		$	0.8700			$	0.8625