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                                                                       EXHIBIT 5
 
                                August 25, 1994
 
California Water Service Company
1720 North First Street
San Jose, CA 95112
 
            CALIFORNIA WATER SERVICE COMPANY REGISTRATION STATEMENT
 
Ladies and Gentlemen:
 
     We have acted as counsel for California Water Service Company, a California
corporation (the "Company"), in connection with the Registration Statement on
Form S-3 filed by the Company under the Securities Act of 1933, as amended,
relating to the registration of 600,000 shares of the Company's Common Stock, no
par value (the "Shares") which are expected to be issued in accordance with the
terms of the Prospectus included in the Registration Statement.
 
     We are of the opinion that the Shares have been duly authorized and, when
sold pursuant to the terms described in the Registration Statement and in
conformity with applicable state securities laws, will be duly and validly
issued, fully paid and nonassessable.
 
     We hereby consent to the filing of this opinion as Exhibit 5 to the
Registration Statement and to the use of our name under the caption "Legal
Matters" in the Registration Statement and in the Prospectus included therein.
 
                                          Very truly yours,
 
                                          McCutchen, Doyle, Brown & Enersen
 
                                          By           THOMAS G. REDDY
                                                    A Member of the Firm