Form: 10-Q

Quarterly report pursuant to Section 13 or 15(d)

November 8, 2004

EXHIBIT 32.1

Published on November 8, 2004

Exhibit 32


CERTIFICATION
PURSUANT TO 18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO SECTION 906
OF THE SARBANES-OXLEY ACT OF 2002

Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, each of the
undersigned certifies that this Quarterly Report on Form 10-Q for the period
ended September 30, 2004 fully complies with the requirements of Section 13(a)
or 15(d), as applicable, of the Securities Exchange Act of 1934 and that the
information contained in this Report fairly presents, in all material respects,
the financial condition and results of operations of California Water Service
Group.




Date: November 5, 2004 /s/ Peter C. Nelson
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PETER C. NELSON
Chief Executive Officer
California Water Service Group



Date: November 5, 2004 By: /s/ Richard D. Nye
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RICHARD D. NYE
Chief Financial Officer
California Water Service Group