Cal Water Announces Intention to Offer $100 Million of First Mortgage Bonds

SAN JOSE, CA -- (MARKET WIRE) -- 11/16/10 -- California Water Service Group (NYSE: CWT) announced today that California Water Service Company ("Cal Water" or the "Company"), a wholly owned subsidiary of California Water Service Group, intends to offer and sell, subject to market and other conditions, $100 million principal amount of first mortgage bonds, which will be fully and unconditionally guaranteed by California Water Service Group. Robert W. Baird & Co. and Blaylock Robert Van, LLC are acting as joint book running managers for the offering.

The Company plans to use a portion of the net proceeds from the sale of the bonds to pay down outstanding short-term borrowings. Further, the Company plans to add the remainder of the net proceeds to its general funds to be used for general corporate purposes, including capital projects.

This announcement is neither an offer to sell nor a solicitation of an offer to buy any of these securities and shall not constitute an offer, solicitation, or sale in any jurisdiction in which such offer, solicitation, or sale is unlawful.

Copies of the Prospectus Supplement and accompanying Prospectus relating to the offering may be obtained from Robert W. Baird & Co. Incorporated, Fixed Income Department, 777 East Wisconsin Avenue, Milwaukee, WI 53202, or by calling 1-800-RWBAIRD (1-800-792-2473).

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., CWS Utility Services, and HWS Utility Services. Together these companies provide regulated and non-regulated water service to nearly 2 million people in California, Washington, New Mexico, and Hawaii. California Water Service Group's common stock trades on the New York Stock Exchange under the symbol "CWT."

The matters discussed in this release include forward-looking statements. These statements are based on current expectations or beliefs and are subject to factors and uncertainties that could cause actual results to differ materially from those described in the forward-looking statements, including without limitation, whether or not Cal Water will offer the first mortgage bonds or consummate the offering, the anticipated terms of the first mortgage bonds and the offering, and the anticipated use of the proceeds of the offering. California Water Service Group is providing this information as of the date of this news release and assumes no obligation to update any forward-looking statement to reflect events or circumstances occurring after the date of this press release.

Additional information is available on our website at www.calwatergroup.com.

Released November 16, 2010