Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2025
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies H2O America and its subsidiaries are subject to ordinary routine litigation incidental to its business. In October 2023, CWC, a subsidiary of H2O America, was named as a defendant in a putative class action lawsuit alleging that the water provided by CWC contained contaminants. The case is currently pending in the State of Connecticut Superior Court. CWC intends to vigorously defend itself in this lawsuit. H2O America is unable to provide a reasonable estimate of loss, if any, at this time. SJWC and CWC are plaintiffs in a lawsuit against manufacturers of certain PFAS compounds for damages, contribution and reimbursement of costs incurred and continuing to be incurred to address the presence of such PFAS compounds in public water supply systems owned and operated by these utility subsidiaries and throughout their respective service areas. The lawsuit is part of Multi-District Litigation (“MDL”) that commenced on December 7, 2018, in the United States District Court for the District of South Carolina. MWC has submitted timely claims as a settlement class member. On February 8, 2024, the MDL court approved settlements involving defendants The Chemours Company, Corteva, Inc., and DuPont de Nemours, Inc. to resolve claims brought in the MDL against them by public water systems, including SJWC and CWC. On March 29, 2024, the MDL court approved a similar settlement involving defendant 3M Company. On November 22, 2024, the MDL court approved settlements involving defendants Tyco Fire Products LP and BASF Corporation. H2O America is entitled to a portion of the settlements and is monitoring and evaluating the ongoing litigation and settlement activity with the PFAS manufacturers for potential impacts to the various claims that these utility subsidiaries have asserted. For the three and nine months ended September 30, 2025, the Company received cash proceeds of $14,710 and $21,152, respectively, in connection with a legal settlement with 3M Company related to PFAS contamination. In the third quarter of 2025, the total proceeds of $14,710 were allocated as follows: SJWC received $10,078; CWC received $4,571; and MWC received $61. For the nine months ended September 30, 2025, the total proceeds of $21,152 were allocated as follows: SJWC received $14,497; CWC received $6,477; and MWC received $178, which includes $91 payable to contract operators. The proceeds are compensatory in nature and are intended to reimburse the Company for costs incurred to address the presence of PFAS compounds in public water supply systems or to be refunded to customers through rate reductions, and have been recorded as a regulatory liability subject to regulatory approval. H2O America is entitled to receive additional cash proceeds from 3M Company in the subsequent nine years, pursuant to the terms of the settlement agreement. In addition, the Company is party to pending settlements with DuPont de Nemours, Inc., Tyco Fire Products LP, and BASF Corporation. Proceeds from these settlements are also expected to be received in 2025 and will be accounted for in a manner consistent with the 3M Company settlement. H2O America is monitoring and evaluating the ongoing litigation and settlement activity with the PFAS manufacturers for potential impacts to the various claims that these utility subsidiaries have asserted. However, the amount of these additional proceeds is not estimable as of the date of this filing.