Regulatory Rate Filings	3 Months Ended
Mar. 31, 2018
Regulated Operations [Abstract]
Regulatory Rate Filings	Regulatory Rate Filings On November 15, 2017, San Jose Water Company filed Advice Letter No. 513/513A with the CPUC requesting a revenue increase of $15,670, or 4.22%, for the 2018 escalation year included in the 2015 General Rate Case. This request was approved and the new rates became effective on January 1, 2018. On November 29, 2017, San Jose Water Company filed Advice Letter No. 514 with the CPUC requesting to adjust the Utilities Reimbursement Account User Fees as directed by CPUC Resolution M-4832. The reimbursement fee was reduced from 1.44% to 1.40%. This request was approved and the new fee became effective on January 1, 2018. San Jose Water Company filed Advice Letter No. 515 on December 28, 2017, with the CPUC requesting authorization to establish the 2018 Tax Accounting Memorandum Account. This memorandum account will capture any changes to revenue requirement resulting from the impact of the Tax Act signed into law December 22, 2017. This request became effective on January 1, 2018. On January 6, 2017, San Jose Water Company filed Advice Letter No. 501 with the CPUC requesting authorization to implement a sales reconciliation mechanism to better conform to water forecasts authorized in the last general rate case to recorded consumption for the period of October 2015 through September 2016. The CPUC ordered all Class A and B water utilities that have a five percent or greater divergence between authorized and actual sales during declared drought years to consider requesting a sales reconciliation mechanism to better conform to sale forecasts authorized in the last general rate case to recorded consumption. On May 3, 2017, the CPUC rejected the filing citing the end of a drought and the improved California water supply conditions. On May 10, 2017, San Jose Water Company formally requested the CPUC’s review of the rejection. On August 25, 2017, the CPUC’s Water Division released Proposed Resolution W-5150 affirming its rejection of Advice Letter No. 501. On September 20, 2017, Revision 1 to Proposed Resolution W-5150 was released by the Water Division. A revised resolution, Proposed Resolution W-5153, was circulated on December 8, 2017, for comment and also affirmed the rejection of Advice Letter No. 501. Subsequently, the resolution to reject Advice Letter No. 501 was approved by CPUC on January 11, 2018. As required by the CPUC, on April 3, 2017, San Jose Water Company filed an application requesting authority to increase its authorized Cost of Capital for the period from January 1, 2018 through December 31, 2020. On March 22, 2018, the CPUC approved a new cost of capital for San Jose Water Company in Decision 18-03-035 that lowers the rate of return from 8.09% to 7.64% thereby reducing the 2018 revenue requirement by $5,843 or 1.57%. On March 22, 2018, San Jose Water Company filed Advice Letter No. 518 with the CPUC requesting authorization to adjust water rates to reflect the decision effective March 22, 2018. On January 4, 2018, San Jose Water Company filed General Rate Case Application No. 18-01-004 requesting authority for an increase of revenue of $34,288, or 9.76%, in 2019, $14,232, or 3.70%, in 2020 and $20,582, or 5.17%, in 2021. The application also includes requests to recover $20,725 from balancing and memorandum accounts, the establishment of a Water Revenue Adjustment Mechanism and Sales Reconciliation Mechanism, and a shift to greater revenue collection in the service charge. The application is a year-long review process and new rates, if approved, are expected to be effective January 1, 2019. On March 14, 2018, San Jose Water Company filed Advice Letter No. 517 to update its Cost of Capital Memorandum Account, which tracks the difference between current water rates and those adopted in Decision 18-03-035. This was approved on April 4, 2018. On March 23, 2018, San Jose Water Company filed Advice Letter No. 519 with the CPUC requesting authorization to update the Rule 15 income tax provisions as a result of the recent changes to the federal tax laws. This advice letter has no impact on water rates and was effective January 1, 2018. The Public Utilities Commission of Texas (“PUCT”) has directed CLWSC (as well as other Class A water utilities in Texas) to quantify all of the impacts of the Tax Act and make rate adjustments reflecting these impacts on a prospective basis. PUCT Order 47945-36 as amended by 47945-41 orders the water utilities to record a regulatory liability that reflects (1) the difference between the revenues collected under existing rates and the revenues that would have been collected had the existing rates been set using the recently approved federal income tax rates; and (2) the balance of excess accumulated deferred federal income taxes that now exists because of the decrease in the federal income tax rate from 35% to 21%. A rate proposal reflecting these tax changes was submitted for PUCT review on April 19, 2018. If adopted as proposed, the revenue requirement for CLWSC will be reduced by about $745 for 2018, with new rates becoming effective for billings on or about May 1, 2018. As of March 31, 2018, CLWSC has recorded a Tax Act regulatory liability in the amount of $139. On May 4, 2018, SJW Group and CTWS filed with the Connecticut Public Utilities Regulatory Authority and the Maine Public Utilities Commission applications for the approval of the proposed merger (see discussion on the proposed merger at Note 12).

Regulatory Rate Filings

On November 15, 2017, San Jose Water Company filed Advice Letter No. 513/513A with the CPUC requesting a revenue increase of $15,670, or 4.22%, for the 2018 escalation year included in the 2015 General Rate Case. This request was approved and the new rates became effective on January 1, 2018.

On November 29, 2017, San Jose Water Company filed Advice Letter No. 514 with the CPUC requesting to adjust the Utilities Reimbursement Account User Fees as directed by CPUC Resolution M-4832. The reimbursement fee was reduced from 1.44% to 1.40%. This request was approved and the new fee became effective on January 1, 2018.

San Jose Water Company filed Advice Letter No. 515 on December 28, 2017, with the CPUC requesting authorization to establish the 2018 Tax Accounting Memorandum Account. This memorandum account will capture any changes to revenue requirement resulting from the impact of the Tax Act signed into law December 22, 2017. This request became effective on January 1, 2018.

On January 6, 2017, San Jose Water Company filed Advice Letter No. 501 with the CPUC requesting authorization to implement a sales reconciliation mechanism to better conform to water forecasts authorized in the last general rate case to recorded consumption for the period of October 2015 through September 2016. The CPUC ordered all Class A and B water utilities that have a five percent or greater divergence between authorized and actual sales during declared drought years to consider requesting a sales reconciliation mechanism to better conform to sale forecasts authorized in the last general rate case to recorded consumption. On May 3, 2017, the CPUC rejected the filing citing the end of a drought and the improved California water supply conditions. On May 10, 2017, San Jose Water Company formally requested the CPUC’s review of the rejection. On August 25, 2017, the CPUC’s Water Division released Proposed Resolution W-5150 affirming its rejection of Advice Letter No. 501. On September 20, 2017, Revision 1 to Proposed Resolution W-5150 was released by the Water Division. A revised resolution, Proposed Resolution W-5153, was circulated on December 8, 2017, for comment and also affirmed the rejection of Advice Letter No. 501. Subsequently, the resolution to reject Advice Letter No. 501 was approved by CPUC on January 11, 2018.

As required by the CPUC, on April 3, 2017, San Jose Water Company filed an application requesting authority to increase its authorized Cost of Capital for the period from January 1, 2018 through December 31, 2020. On March 22, 2018, the CPUC approved a new cost of capital for San Jose Water Company in Decision 18-03-035 that lowers the rate of return from 8.09% to 7.64% thereby reducing the 2018 revenue requirement by $5,843 or 1.57%. On March 22, 2018, San Jose Water Company filed Advice Letter No. 518 with the CPUC requesting authorization to adjust water rates to reflect the decision effective March 22, 2018.

On January 4, 2018, San Jose Water Company filed General Rate Case Application No. 18-01-004 requesting authority for an increase of revenue of $34,288, or 9.76%, in 2019, $14,232, or 3.70%, in 2020 and $20,582, or 5.17%, in 2021. The application also includes requests to recover $20,725 from balancing and memorandum accounts, the establishment of a Water Revenue Adjustment Mechanism and Sales Reconciliation Mechanism, and a shift to greater revenue collection in the service charge. The application is a year-long review process and new rates, if approved, are expected to be effective January 1, 2019.

On March 14, 2018, San Jose Water Company filed Advice Letter No. 517 to update its Cost of Capital Memorandum Account, which tracks the difference between current water rates and those adopted in Decision 18-03-035. This was approved on April 4, 2018.

On March 23, 2018, San Jose Water Company filed Advice Letter No. 519 with the CPUC requesting authorization to update the Rule 15 income tax provisions as a result of the recent changes to the federal tax laws. This advice letter has no impact on water rates and was effective January 1, 2018.

The Public Utilities Commission of Texas (“PUCT”) has directed CLWSC (as well as other Class A water utilities in Texas) to quantify all of the impacts of the Tax Act and make rate adjustments reflecting these impacts on a prospective basis. PUCT Order 47945-36 as amended by 47945-41 orders the water utilities to record a regulatory liability that reflects (1) the difference between the revenues collected under existing rates and the revenues that would have been collected had the existing rates been set using the recently approved federal income tax rates; and (2) the balance of excess accumulated deferred federal income taxes that now exists because of the decrease in the federal income tax rate from 35% to 21%. A rate proposal reflecting these tax changes was submitted for PUCT review on April 19, 2018. If adopted as proposed, the revenue requirement for CLWSC will be reduced by about $745 for 2018, with new rates becoming effective for billings on or about May 1, 2018. As of March 31, 2018, CLWSC has recorded a Tax Act regulatory liability in the amount of $139.

On May 4, 2018, SJW Group and CTWS filed with the Connecticut Public Utilities Regulatory Authority and the Maine Public Utilities Commission applications for the approval of the proposed merger (see discussion on the proposed merger at Note 12).