EXHIBIT 32.1
Published on November 6, 2007
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 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, 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: November 6, 2007 | By: | /s/ Peter C. Nelson | ||
| PETER C. NELSON | ||||
| Chief Executive Officer California Water Service Group |
||||
| Date: November 6, 2007 | By: | /s/ Martin A. Kropelnicki | ||
| MARTIN A. KROPELNICKI | ||||
| Chief Financial Officer California Water Service Group |
||||