Form: 10-Q

Quarterly report pursuant to Section 13 or 15(d)

August 6, 2008

         
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, 2008, 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 6, 2008 
By:  /s/ Peter C. Nelson    
    PETER C. NELSON   
    Chief Executive Officer
California Water Service Group 
 
 
     
Date: August 6, 2008 
  By:  /s/ Martin A. Kropelnicki    
    MARTIN A. KROPELNICKI   
    Chief Financial Officer
California Water Service Group