Contingencies:	9 Months Ended
Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Contingencies: Condemnation of Properties: The laws of the State of California provide for the acquisition of public utility property by governmental agencies through their power of eminent domain, also known as condemnation, where doing so is necessary and in the public interest. In addition, these laws provide that the owner of utility property (i) may contest whether the condemnation is actually necessary and in the public interest, and (ii) is entitled to receive the fair market value of its property if it is ultimately taken. Claremont System: In December 2014, the City of Claremont, California filed a complaint in eminent domain against GSWC. GSWC is in the process of vigorously defending against the eminent domain action. Closing arguments for the phase of the trial determining Claremont's right to seize the system by eminent domain concluded in August 2016, with a decision expected within 90 days after the closing arguments. At this time, management cannot predict the outcome of this eminent domain proceeding. The Claremont water system has a net book value of approximately $49.3 million. GSWC serves approximately 11,000 customers in Claremont. Ojai System: In March 2013, Casitas Municipal Water District ("CMWD") passed resolutions under the Mello-Roos Communities Facilities District Act of 1982 ("Mello-Roos Act") authorizing the establishment of a Community Facilities District, and the issuance of bonds to finance the potential acquisition of GSWC’s Ojai, California system through eminent domain. In January 2014, a group of citizens referred to as "Friends of Locally Owned Water" ("FLOW") were granted class status to allow them to later file a complaint against GSWC for damages related to any potential delay in the eminent domain proceedings caused by GSWC’s challenge of CMWD’s use of Mello-Roos funds for such a taking of property. On May 12, 2016, CMWD filed a complaint in eminent domain against GSWC. The complaint also included additional causes of action related to claims of potential damages resulting from any delay caused by GSWC seeking relief in the prior action regarding the use of Mello-Roos funds for such a taking of property. On June 28, 2016, FLOW filed for intervention as a plaintiff to also seek potential damages resulting from the additional causes of actions listed above as facilitated in their earlier filing to be granted class status. On October 25, 2016, the Court struck FLOW’s complaint in intervention and their claims for damages. At this time, management cannot predict whether FLOW will appeal the Court’s ruling, and cannot predict the outcome of this eminent domain proceeding. The Ojai water system has a net book value of approximately $22.4 million. GSWC serves approximately 3,000 customers in Ojai. Environmental Clean-Up and Remediation: GSWC has been involved in environmental remediation and clean-up at a plant site that contained an underground storage tank which was used to store gasoline for its vehicles. This tank was removed from the ground in July 1990 along with the dispenser and ancillary piping. Since then, GSWC has been involved in various remediation activities at this site. As of September 30, 2016, the total amount spent to clean-up and remediate GSWC’s plant facility was approximately $5.1 million, of which $1.5 million has been paid by the State of California Underground Storage Tank Fund. Amounts paid by GSWC have been included in rate base and approved by the CPUC for recovery. As of September 30, 2016, GSWC has a regulatory asset and an accrued liability for the estimated additional cost of $1.4 million to complete the clean-up at the site. The estimate includes costs for two years of continued activities of cleanup and monitoring, and site-closure-related activities. The ultimate cost may vary as there are many unknowns in remediation of underground gasoline spills and this is an estimate based on currently available information. Management believes it is probable that the estimated additional costs will be approved in rate base by the CPUC. Other Litigation: Registrant is also subject to other ordinary routine litigation incidental to its business. Management believes that rate recovery, proper insurance coverage and reserves are in place to insure against property, general liability and workers’ compensation claims incurred in the ordinary course of business. Registrant is unable to predict an estimate of the loss, if any, resulting from any pending suits or administrative proceedings.

Contingencies:

Condemnation of Properties:

The laws of the State of California provide for the acquisition of public utility property by governmental agencies through their power of eminent domain, also known as condemnation, where doing so is necessary and in the public interest. In addition, these laws provide that the owner of utility property (i) may contest whether the condemnation is actually necessary and in the public interest, and (ii) is entitled to receive the fair market value of its property if it is ultimately taken.

Claremont System:

In December 2014, the City of Claremont, California filed a complaint in eminent domain against GSWC. GSWC is in the process of vigorously defending against the eminent domain action. Closing arguments for the phase of the trial determining Claremont's right to seize the system by eminent domain concluded in August 2016, with a decision expected within 90 days after the closing arguments. At this time, management cannot predict the outcome of this eminent domain proceeding. The Claremont water system has a net book value of approximately $49.3 million. GSWC serves approximately 11,000 customers in Claremont.

Ojai System:

In March 2013, Casitas Municipal Water District ("CMWD") passed resolutions under the Mello-Roos Communities Facilities District Act of 1982 ("Mello-Roos Act") authorizing the establishment of a Community Facilities District, and the issuance of bonds to finance the potential acquisition of GSWC’s Ojai, California system through eminent domain. In January 2014, a group of citizens referred to as "Friends of Locally Owned Water" ("FLOW") were granted class status to allow them to later file a complaint against GSWC for damages related to any potential delay in the eminent domain proceedings caused by GSWC’s challenge of CMWD’s use of Mello-Roos funds for such a taking of property.

On May 12, 2016, CMWD filed a complaint in eminent domain against GSWC. The complaint also included additional causes of action related to claims of potential damages resulting from any delay caused by GSWC seeking relief in the prior action regarding the use of Mello-Roos funds for such a taking of property. On June 28, 2016, FLOW filed for

intervention as a plaintiff to also seek potential damages resulting from the additional causes of actions listed above as facilitated in their earlier filing to be granted class status. On October 25, 2016, the Court struck FLOW’s complaint in intervention and their claims for damages. At this time, management cannot predict whether FLOW will appeal the Court’s ruling, and cannot predict the outcome of this eminent domain proceeding. The Ojai water system has a net book value of approximately $22.4 million. GSWC serves approximately 3,000 customers in Ojai.

Environmental Clean-Up and Remediation:

GSWC has been involved in environmental remediation and clean-up at a plant site that contained an underground storage tank which was used to store gasoline for its vehicles. This tank was removed from the ground in July 1990 along with the dispenser and ancillary piping. Since then, GSWC has been involved in various remediation activities at this site.

As of September 30, 2016, the total amount spent to clean-up and remediate GSWC’s plant facility was approximately $5.1 million, of which $1.5 million has been paid by the State of California Underground Storage Tank Fund. Amounts paid by GSWC have been included in rate base and approved by the CPUC for recovery. As of September 30, 2016, GSWC has a regulatory asset and an accrued liability for the estimated additional cost of $1.4 million to complete the clean-up at the site. The estimate includes costs for two years of continued activities of cleanup and monitoring, and site-closure-related activities. The ultimate cost may vary as there are many unknowns in remediation of underground gasoline spills and this is an estimate based on currently available information. Management believes it is probable that the estimated additional costs will be approved in rate base by the CPUC.

Other Litigation:

Registrant is also subject to other ordinary routine litigation incidental to its business. Management believes that rate recovery, proper insurance coverage and reserves are in place to insure against property, general liability and workers’ compensation claims incurred in the ordinary course of business. Registrant is unable to predict an estimate of the loss, if any, resulting from any pending suits or administrative proceedings.