Press Release

California Water Service Group Schedules Fourth Quarter and Year-End 2009 Earnings Results Announcement and Teleconference

SAN JOSE, CA, Feb 01, 2010 (MARKETWIRE via COMTEX) -- California Water Service Group (NYSE: CWT) today announced that its fourth quarter and year-end earnings results will be released after the market-close on Wednesday, February 24, 2010, and its teleconference will be held at 11:00 a.m. EST on Thursday, February 25, 2010.

All stockholders and interested investors are invited to listen to the teleconference. The 2009 fourth quarter and year-end conference call may be accessed by dialing 1-866-837-9789 and keying in ID# 1427079. A replay of the call will be available from 2:00 p.m. EST on Thursday, February 25, 2010, through April 26, 2010, at 888-258-7854, ID# 1427079. The call, which will be hosted by Vice President & Chief Financial Officer Martin A. Kropelnicki and President & Chief Executive Officer Peter C. Nelson, 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., CWS Utility Services, and HWS 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. Group's common stock trades on the New York Stock Exchange under the symbol "CWT."

1720 North First Street
San Jose, CA 95112-4598

Contact:
Shannon Dean
(310) 257-1435

SOURCE: California Water Service Group