SJW (SJW) 10-K 2012 FY Annual report

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Annual Report of SJW Corp. (the “Company”) on Form 10-K for the year ended December 31, 2012, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, W. Richard Roth, President and Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to my knowledge on the date hereof:

(1) the Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2) the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ W. Richard Roth

W. RICHARD ROTH

President, Chief Executive Officer and

Chairman of the Board

(Principal executive officer)

February 28, 2013