Commitments	12 Months Ended
Commitments	Dec. 31, 2020
Commitments Disclosure [Abstract]
Commitments	Commitments SJWC purchases water from Valley Water under terms of a master contract expiring in 2051. Delivery schedules for purchased water are based on a contract year beginning July 1, and are negotiated every three years under terms of the master contract with Valley Water. For the years ended December 31, 2020, 2019 and 2018, SJWC purchased from Valley Water 21,269 million gallons ($96,212), 21,862 million gallons ($96,285) and 21,345 million gallons ($87,702), respectively, of contract water. On June 22, 2020, the Valley Water Board of Directors approved treated water deliveries reflecting the contractual delivery schedule reduced by 10% through June 30, 2021. Based on current prices and estimated deliveries, SJWC is committed to purchase from Valley Water a minimum of 90% of the reduced delivery schedule, or 19,794 million gallons ($89,539) of water at the current contract water rate of $4.5 per million gallons for the year ending December 31, 2021. Additionally, SJWC purchases non-contract water from Valley Water on an “as needed” basis if the water supply is available. In 1997, SJWC entered into a 25-year contract agreement with the City of Cupertino to operate the City’s municipal water system. SJWC paid a one-time, upfront concession fee of $6,800 to the City of Cupertino which is amortized over the contract term. Under the terms of the contract agreement, SJWC assumed responsibility for maintenance and operating costs, while receiving all payments for water service. SJWC and the City of Cupertino signed an amendment to the lease agreement dated January 8, 2020. Under the terms of the amended lease agreement, SJWC agreed to an incremental up-front payment of $5,000 to be used by the City of Cupertino for capital improvements to the City’s municipal water system prior to the expiration of the lease in September 2022. Any unspent funds at lease termination remain the property of the City. Connecticut Water has an agreement with the South Central Connecticut Regional Water Authority (“RWA”) to purchase water from RWA. The agreement was signed in April 2006 and became effective upon the receipt of all regulatory approvals in 2008 and will remain in effect for a minimum of fifty years upon becoming effective. Connecticut Water will pay RWA $75 per year as part of a capacity agreement, for a total of 14 years, starting on the effective date of the agreement. In addition, Connecticut Water is able, but under no obligation, to purchase up to one million gallons of water per day at the then current wholesale rates per the agreement, $2.621 per million gallons as of December 31, 2020. Connecticut Water has an agreement with The Metropolitan District (“MDC”) to purchase water from MDC to serve the Unionville system. The agreement became effective on October 6, 2000 and has a term of fifty years beginning May 19, 2003, the date the water supply facilities related to the agreement were placed in service. Connecticut Water agrees to purchase 283 million gallons of water annually from MDC. The rate charged by the MDC at December 31, 2020 were $3.97 per hundred cubic feet. CLWSC has long-term contracts with the GBRA. The terms of the agreements expire in 2037, 2040, 2044 and 2050. The agreements, which are take-or-pay contracts, provide CLWSC with 6,900 acre-feet per year of water supply from Canyon Lake. The water rate may be adjusted by GBRA at any time, provided they give CLWSC a 60-day written notice on the proposed adjustment. CLWSC also has raw water supply agreements with the Lower Colorado River Authority (“LCRA”) and West Travis Public Utility Agency (“WTPUA”) expiring in 2059 and 2046, respectively, for 250 acre-feet of water under each agreement per year from Lake Austin and the Colorado River, respectively, at prices that may be adjusted periodically by the agencies. Maine Water has an agreement with the Kennebec Water District for potable water service. The agreement has been in place for 20 years and was extended on November 7, 2020 for a new term of up to 20 years. Maine Water guarantees a minimum consumption of 50 million gallons of water annually. Water sales to Maine Water are billed at a wholesale discount of $0.20 per hundred cubic feet of water below Kennebec Water District's tariffed rates. The current tariff rate was $1.51 per hundred cubic feet as of December 31, 2020. As of December 31, 2020, SJWC had 370 employees, of whom 137 were executive, administrative or supervisory personnel, and of whom 233 were members of unions. On November 12, 2019 and February 20, 2020, SJWC reached three-year bargaining agreements with the International Union of Operating Engineers, representing certain employees in the engineering department, and the Utility Workers of America, representing the majority of all nonadministrative employees at SJWC, respectively, covering January 1, 2020 through December 31, 2022. The agreements include a 3% wage increase in 2020, 3% in 2021 and 4% in 2022 for members of both unions.