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 June 30, 2007, 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: August 7, 2007		By: /s/ Peter C. Nelson
				PETER C. NELSON
				Chief Executive Officer
				California Water Service Group
		Date: August 7, 2007		By: /s/ Martin A. Kropelnicki
				MARTIN A. KROPELNICKI
				Chief Financial Officer
				California Water Service Group