COMMITMENTS AND CONTINGENCIES - Narrative (Details)		1 Months Ended	12 Months Ended
	Dec. 20, 2017 USD ($)	Jan. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) well
Long-term purchase commitments - other disclosures
Operating lease renewal term			25 years
Finance lease renewal term			25 years
Contingency loss recognized liability				$ 5,300,000
Supply Commitment | Camino Real
Long-term purchase commitments - other disclosures
Payments for other commitments			$ 21,500,000
Supply Commitment | Camino Real | Subsequent Event
Long-term purchase commitments - other disclosures
Payments for other commitments		$ 11,100,000
Minimum
Long-term purchase commitments - other disclosures
Operating lease term			1 year
Finance lease term			1 year
Maximum
Long-term purchase commitments - other disclosures
Operating lease term			50 years
Finance lease term			50 years
Kern County Water Agency (Agency)
Long-term purchase commitments - other disclosures
Total capital facilities charge and treated water charge obligation per acre foot			$ 510.67
Portion of estimated operating cost per acre foot for treated water delivered			$ 72.58
California Water Service Company and City of Bakersfield v. The Dow Chemical Company, et al., Civil Case No. CIV-470999 (TCP Action)
Long-term purchase commitments - other disclosures
Amount awarded	$ 85,000,000
Proceeds from legal settlements	$ 56,000,000
Claims settled | well				47
Pending claims | well				57
Claims dismissed | well				36