Lines of Credit	12 Months Ended
Dec. 31, 2011
Lines of Credit [Abstract]
Short-term Debt [Text Block]	Lines of Credit On July 1, 2011, SJW Corp., SJW Land Company and Wells Fargo Bank, National Association entered into an amendment to their credit agreement dated May 27, 2010, as amended on December 16, 2010, to decrease the maximum principal amount available under the line of credit from $45,000 to $10,000 and to modify the covenants regarding SJW Corp.'s funded debt to capitalization ratio and earnings before interest and taxes coverage ratio. On July 1, 2011, San Jose Water Company and Wells Fargo Bank, National Association entered into an amendment to their credit agreement dated May 27, 2010, as amended December 16, 2010, to increase the maximum principal amount available under the line of credit from $50,000 to $75,000 and to modify the earnings before interest and taxes coverage ratio covenant. As of December 31, 2011, SJW Corp. and its subsidiaries had unsecured bank lines of credit, allowing aggregate short-term borrowings of up to $85,000. San Jose Water Company issued two standby letters of credit with a commercial bank in the amount of $3,000 in support of its SDWSRF loans which were funded in 2005 and 2008. The letters of credit automatically renew for one year each December unless the issuing bank elects not to renew it, and the amount of coverage can be reduced as the loan principal balance decreases. As of December 31, 2011, $3,000 under the San Jose Water Company line of credit is set aside as security for its SDWSRF loans. These lines of credit bear interest at variable rates and expire on June 1, 2012. As of December 31, 2011 and 2010, SJW Corp. has an outstanding balance on the lines of credit of $0 and $4,000, respectively. Cost of borrowing on the lines of credit averaged 1.64% and 1.98% as of December 31, 2011 and 2010, respectively.

Lines of Credit

12 Months Ended

Dec. 31, 2011

Lines of Credit

On July 1, 2011, SJW Corp., SJW Land Company and Wells Fargo Bank, National Association entered into an amendment to their credit agreement dated May 27, 2010, as amended on December 16, 2010, to decrease the maximum principal amount available under the line of credit from $45,000 to $10,000 and to modify the covenants regarding SJW Corp.'s funded debt to capitalization ratio and earnings before interest and taxes coverage ratio.

On July 1, 2011, San Jose Water Company and Wells Fargo Bank, National Association entered into an amendment to their credit agreement dated May 27, 2010, as amended December 16, 2010, to increase the maximum principal amount available under the line of credit from $50,000 to $75,000 and to modify the earnings before interest and taxes coverage ratio covenant.

As of December 31, 2011, SJW Corp. and its subsidiaries had unsecured bank lines of credit, allowing aggregate short-term borrowings of up to $85,000. San Jose Water Company issued two standby letters of credit with a commercial bank in the amount of $3,000 in support of its SDWSRF loans which were funded in 2005 and 2008. The letters of credit automatically renew for one year each December unless the issuing bank elects not to renew it, and the amount of coverage can be reduced as the loan principal balance decreases. As of December 31, 2011, $3,000 under the San Jose Water Company line of credit is set aside as security for its SDWSRF loans. These lines of credit bear interest at variable rates and expire on June 1, 2012. As of December 31, 2011 and 2010, SJW Corp. has an outstanding balance on the lines of credit of $0 and $4,000, respectively. Cost of borrowing on the lines of credit averaged 1.64% and 1.98% as of December 31, 2011 and 2010, respectively.