Organization and Operations	12 Months Ended
Organization and Operations	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Operations	Organization and Operations The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of SJW Group, its wholly owned subsidiaries, and two variable interest entities in which two SJW Group subsidiaries are the primary beneficiaries. The accounting policies of SJW Group’s subsidiaries comply with the applicable uniform system of accounts prescribed by the respective regulators. All intercompany transactions and balances have been eliminated in consolidation. The accounting policies of SJW Group’s subsidiaries comply with the applicable uniform system of accounts prescribed by the respective regulators and conform to generally accepted accounting principles for rate-regulated public utilities. SJW Group’s subsidiaries are as follows: San Jose Water Company (“SJWC”), is a regulated California water utility providing water service to approximately 231,000 connections that serve approximately one million people in the greater metropolitan San Jose area. Approximately 92% of SJWC’s revenues are derived from the sale of water to residential and business customers. SJWNE, LLC is a special purpose entity holding company for SJW Group’s investment in Connecticut Water Service, Inc. Connecticut Water Service, Inc., headquartered in Connecticut, is a holding company for water utilities companies providing water service to approximately 140,000 connections that serve a population of approximately 456,000 people in 81 municipalities throughout Connecticut and Maine and more than 3,000 wastewater connections in Southbury, Connecticut. Connecticut Water Service, Inc. and its subsidiaries (“CTWS”) became a wholly-owned subsidiary of SJWNE LLC which is a wholly-owned subsidiary of SJW Group (see, Note 1 4, “Business Combinations”) in 2019. The subsidiaries held by Connecticut Water Service, Inc. that provide utility water services are The Connecticut Water Company (“Connecticut Water”) and The Maine Water Company (“Maine Water”). The remaining two subsidiaries are Chester Realty, Inc., a real estate company in Connecticut, and New England Water Utility Services, Inc. (“NEWUS”), which provides contract water and sewer operations and other water related services. SJWTX, Inc. is doing business as Canyon Lake Water Service Company (“CLWSC”). CLWSC is a public utility in the business of providing water service to approximately 24,000 service connections that serve a population of approximately 70,000 people. CLWSC’s service area comprises more than 266 square miles in the southern region of the Texas Hill Country in Bandera, Blanco, Comal, Hays, Kendall, Medina and Travis counties, the growing region between San Antonio and Austin, Texas. On December 17, 2021, CLWSC completed its acquisition of Kendall West Utility and Bandera East Utility, companies that provide water services, including wastewater and recycled water services, in Kendall, Bandera and Medina counties which are located in south central Texas. Kendall West Utility and Bandera East Utility, together, added approximately 5,000 people through 1,600 service connections in a service area approximately 19 square miles to CLWSC’s operations. SJWTX, Inc. has a 25% interest in Acequia Water Supply Corporation. Acequia has been determined to be a variable interest entity within the scope of ASC Topic 810 with SJWTX, Inc. as the primary beneficiary. As a result, Acequia has been consolidated with SJWTX, Inc. SJWTX, Inc is undergoing a corporate reorganization to separate regulated operations from non-tariffed activities. In November 2021, SJWTX Holdings, Inc. (“SJWTX Holdings”) and Texas Water Operation Services LLC (“TWOS”) were formed for the purpose of effecting a corporate reorganization of our water services organization in Texas. TWOS was created for non-tariffed operations and is wholly-owned by SJWTX Holdings. SJWTX Holdings is a wholly-owned subsidiary of SJW Group, incorporated to hold the investments in SJWTX, Inc. and TWOS. In addition, in 2022, SJWTX Holdings intends to create a new subsidiary to hold future wholesale water supply assets. SJW Land Company owns a commercial property and undeveloped real estate property in the states of California and Tennessee and owns and operates commercial properties in the state of Tennessee. Water sales are seasonal in nature and influenced by weather conditions. The timing of precipitation and climatic conditions can cause seasonal water consumption by customers to vary significantly. Revenue is generally higher in the warm, dry summer months when water usage and sales are greater and lower in the winter months when cooler temperatures and increased rainfall curtail water usage and sales.