Exhibit 99.1

		NEWS RELEASE CALIFORNIA WATER SERVICE GROUP

		1720 North First Street		August 1, 2007
		San Jose, CA 95112-4598		For Immediate Release
Contact:		Marty Kropelnicki (408) 367-8200 (analysts)
		Shannon Dean (310) 257-1435 (media)

CAL WATER ANNOUNCES SECOND QUARTER 2007 RESULTS AND
COMPANY DECLARES 251ST CONSECUTIVE QUARTERLY DIVIDEND

     SAN JOSE, CA — California Water Service Group (NYSE : CWT) today announced net income of $7.7 million and earnings per common share of $0.37 for the second quarter of 2007, compared to net income of $5.7 million and earnings of $0.31 per common share in the second quarter of 2006.

     Revenues increased by $14.7 million, or 18%, to $95.8 million, benefiting from a $9.9 million increase in water sales to existing customers, a $4.0 million increase in rates, and $0.8 million in sales to new customers.

     Total operating expenses for the second quarter of 2007 increased by $12.9 million, or 18%, to $84.4 million. Included in this category is a $7.1 million increase in water production costs, due largely to the increase in customer water usage and higher costs for wholesale water purchases.

     Other operations expenses increased $1.9 million, or 8%, to $25.3 million, due partially to an increase of $0.7 million in outside services for various initiatives, including preparation for the 2007 General Rate Case; $0.3 million for California Public Utilities Commission fees, which

are based upon revenues; and an increase of $0.2 million in general payroll increases that took effect January 2007.

     Maintenance expense increased by $1.8 million, or 53%, to $5.2 million for the quarter, due to an increase in repairs to water mains and services.

     Depreciation expense increased $0.7 million, or 10%, to $8.4 million, as a result of increases in 2006 utility plant.

     Property and taxes other than income taxes increased $0.4 million, or 13%, to $3.4 million, as a result of higher franchise fees and property taxes, while total income taxes increased $1.3 million, or 32%, to $5.4 million because of higher pre-tax income.

     Other income increased $0.4 million, or 88%, to $0.8 million, mainly due to interest on short-term and other investments. There were no property sales in the second quarter of 2007, compared to property sales of $0.3 million in the second quarter of 2006.

     For the six months ended June 30, 2007, net income increased $2.8 million, or 42%, to $9.3 million, compared to $6.5 million for the same period in the previous year. Earnings per share increased $0.10, or 27%, to $0.45, compared to $0.35 for the same period. Revenues for the six months increased $21.0 million, or 14%, to $167.4 million, compared to $146.3 million for the same period in the previous year.

     “Continuing dry weather boosted our revenues in the second quarter of 2007, as did our continued efforts to improve the process to recover cost increases in water rates,” said Peter C. Nelson, President and Chief Executive Officer.

     Nelson noted that during the quarter, the company prepared its 2007 General Rate Case (GRC) for its company headquarters and eight districts. As part of this filing, the company requested that it be allowed to recover certain corporate costs associated with health care and employee welfare programs, Sarbanes-Oxley compliance, and general administration expenses. If the company headquarters or centralized services application is approved and adopted by the Commission, Cal Water will be allowed to recover these costs across all districts at once, thus greatly reducing the delay in recovery that occurred previously when company headquarters

costs were phased into rates only as districts filed separate General Rates Cases on a three-year schedule.

     Among the programs proposed by Cal Water in the centralized services filing were additional programs to promote conservation. “We share the Commission’s commitment to encouraging wise water use, and with the recent dry weather, our conservation efforts are more important than ever,” Nelson said.

     At their meeting on July 25, 2007, the Directors of California Water Service Group (NYSE:CWT) declared the Company’s 251^st consecutive quarterly dividend on common stock. The quarterly dividend of $0.2900 will be payable on August 17, 2007, to stockholders of record on August 6, 2007. The Board also declared a regular dividend on Series C preferred stock.

     All stockholders and interested investors are invited to listen to the 2007 second quarter conference call on August 2, 2007, at 11:00 a.m. (EDT), by dialing 1-866-253-5757 and keying in ID# 1100221. A replay of the call will be available from 2:00 p.m. (EDT) on August 2, 2007, through October 1, 2007, at 888-266-2081, ID# 1100221. 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 more than 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 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, but are not limited to: governmental and regulatory commissions’ decisions; changes in regulatory commissions’ policies and procedures; the timeliness of regulatory commissions’ actions concerning rate relief; new legislation; 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, as well as the annual 10-K, Quarterly 10-Q, and other reports filed from time-to-time with the Securities and Exchange Commission (SEC). 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 (3).

CALIFORNIA WATER SERVICE GROUP
CONDENSED CONSOLIDATED BALANCE SHEETS
Unaudited

(In thousands, except per share data)		June 30				December 31
		2007				2006
ASSETS
Utility plant:
Utility plant		$	1,394,883			$	1,344,415
Less accumulated depreciation and amortization			(420,321	)			(402,940	)
Net utility plant			974,562				941,475
Current assets:
Cash and cash equivalents			29,842				60,312
Receivables
Customers			23,050				19,526
Other			6,134				6,700
Unbilled revenue			14,698				11,341
Materials and supplies at average cost			4,742				4,515
Prepaid pension expense			—				1,696
Taxes and other prepaid expenses			5,587				5,534
Total current assets			84,053				109,624
Other assets:
Regulatory assets			93,861				93,785
Other assets			22,008				20,135
Total other assets			115,869				113,920
		$	1,174,484			$	1,165,019
CAPITALIZATION AND LIABILITIES
Capitalization:
Common stock, $.01 par value		$	207			$	207
Additional paid-in capital			211,681				211,513
Retained earnings			163,830				166,582
Total common stockholders’ equity			375,718				378,302
Preferred stock			3,475				3,475
Long-term debt, less current maturities			291,299				291,814
Total capitalization			670,492				673,591
Current liabilities:
Current maturities of long-term debt			1,778				1,778
Accounts payable			37,988				33,130
Accrued expenses and other liabilities			32,503				35,317
Total current liabilities			72,269				70,225
Unamortized investment tax credits			2,541				2,541
Deferred income taxes, net			69,472				69,503
Pension and postretirement benefits other than pensions			48,584				48,584
Regulatory and other liabilities			33,629				33,411
Advances for construction			165,819				157,660
Contributions in aid of construction			111,678				109,504
Commitments and contingencies		$	1,174,484			$	1,165,019

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

For the three months ended:

		June 30,				June 30,
		2007				2006
Operating revenue		$	95,782			$	81,102
Operating expenses:
Water production costs			37,271				30,210
Other operations			25,274				23,399
Maintenance			5,241				3,432
Depreciation and amortization			8,380				7,640
Income taxes			4,792				3,753
Property and other taxes			3,435				3,045
Total operating expenses			84,393				71,479
Net operating income			11,389				9,623
Other income and expenses:
Non-regulated revenue			3,423				2,206
Non-regulated expenses			(1,966	)			(1,800	)
Gain (loss) on sale of non-utility property			(83	)			323
Less: income taxes on other income and expenses			(560	)			(297	)
			814				432
Interest expense:
Interest Expense			4,926				4,970
Less: capitalized interest			(450	)			(625	)
Net interest expense			4,476				4,345
Net income		$	7,727			$	5,710
Earnings per share
Basic		$	0.37			$	0.31
Diluted		$	0.37			$	0.31
Weighted average shares outstanding
Basic			20,666				18,407
Diluted			20,690				18,427
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 six months ended:		June 30,				June 30,
		2007				2006
Operating revenue		$	167,352			$	146,318
Operating expenses:
Water production costs			63,084				51,639
Other operations			48,930				47,187
Maintenance			9,750				7,330
Depreciation and amortization			16,781				15,349
Income taxes			5,336				4,041
Property and other taxes			6,840				6,221
Total operating expenses			150,721				131,767
Net operating income			16,631				14,551
Other income and expenses:
Non-regulated revenue			6,465				4,355
Non-regulated expenses			(3,717	)			(3,339	)
Gain (loss) on sale of non-utility property			(83	)			348
Less: income taxes on other income and expenses			(1,086	)			(556	)
			1,579				808
Interest expense:
Interest Expense			9,852				9,667
Less: capitalized interest			(950	)			(850	)
Net interest expense			8,902				8,817
Net income		$	9,308			$	6,542
Earnings per share
Basic		$	0.45			$	0.35
Diluted		$	0.45			$	0.35
Weighted average shares outstanding
Basic			20,663				18,404
Diluted			20,687				18,427
Dividends per share of common stock		$	0.5800			$	0.5750