Lines of Credit - Schedule of Lines of Credit (Details) - Revolving Credit Facility - Line of Credit - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Line of Credit Facility [Line Items]
Line Limit	$ 350,000,000
Amounts Outstanding	159,578,000	$ 62,996,000
Unused Portion	190,422,000
Syndicated Credit Agreement
Line of Credit Facility [Line Items]
Line Limit	300,000,000
Amounts Outstanding	115,000,000	0
Unused Portion	185,000,000
SJW Group Credit Agreement Maturing August 2027
Line of Credit Facility [Line Items]
Line Limit	50,000,000
Amounts Outstanding	0	0
Unused Portion	50,000,000
SJWC Credit Agreement Maturing August 2027
Line of Credit Facility [Line Items]
Line Limit	140,000,000
Amounts Outstanding	95,000,000	0
Unused Portion	45,000,000
CTWS Credit Agreement Maturing August 2027
Line of Credit Facility [Line Items]
Line Limit	90,000,000
Amounts Outstanding	20,000,000	0
Unused Portion	70,000,000
SJWTX Credit Agreement Maturing August 2027
Line of Credit Facility [Line Items]
Line Limit	20,000,000
Amounts Outstanding	0	0
Unused Portion	20,000,000
CTWS Credit Agreement Maturing December 2023
Line of Credit Facility [Line Items]
Line Limit	10,000,000
Amounts Outstanding	4,578,000	22,996,000
Unused Portion	5,422,000
CTWS Credit Agreement Maturing May 2025
Line of Credit Facility [Line Items]
Line Limit	40,000,000
Amounts Outstanding	40,000,000	$ 40,000,000
Unused Portion	$ 0

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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