Press Release

California Water Service Group Schedules Fourth Quarter & Year-End 2006 Earnings Results Announcement and Teleconference

SAN JOSE, Calif., Feb 01, 2007 (BUSINESS WIRE) -- California Water Service Group (NYSE:CWT) today announced that its fourth quarter earnings is scheduled to be released after the market-close on Wednesday, February 28, 2007, and its teleconference will be held at 11 a.m. EST on Thursday, March 1, 2007.

All stockholders and interested investors are invited to listen to the teleconference. The 2006 fourth quarter and year-end conference call may be accessed by dialing 1-866-802-4290 and keying in ID# 1022927. A replay of the call will be available from 2:00 p.m. EST Thursday, March 1, 2007, through April 30, 2007, at 888-266-2081, ID# 1022927. The call, which will be hosted by Chairman Robert W. Foy 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. Group's common stock trades on the New York Stock Exchange under the symbol "CWT."

SOURCE: California Water Service Group

California Water Service Group
Shannon Dean, 310-257-1435