Income Taxes	3 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	Income TaxesIncome tax expense (benefit) for the three months ended March 31, 2022, and 2021, was $1,067 and $(896), respectively. The effective consolidated income tax rates were 22% and (52)% for the three months ended March 31, 2022, and 2021, respectively. The higher effective tax rate for the three months ended March 31, 2022, was primarily due to discrete tax expense items.SJW Group had unrecognized tax benefits, before the impact of deductions of state taxes, excluding interest and penalties of approximately $8,014 and $7,961 as of March 31, 2022, and December 31, 2021, respectively. SJW Group does not expect its unrecognized tax benefits to change significantly within the next 12 months.