XML 73 R54.htm IDEA: XBRL DOCUMENT
v3.25.4

Regulatory Matters - Schedule of Regulatory Assets, Net (Details) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2025 | Dec. 31, 2024
Regulatory assets: |  |
Total regulatory assets | $ 254,862 | $ 242,227
Less: current regulatory asset | 8,315 | 18,172
Total regulatory assets, less current portion | 246,547 | 224,055
Regulatory liabilities: |  |
Total regulatory liabilities | 546,797 | 484,841
Less: current regulatory liabilities | 0 | 1,122
Total regulatory liabilities, less current portion | $ 546,797 | 483,719
Minimum |  |
Regulatory liabilities: |  |
Estimated service lives of assets | 5 years |
Maximum |  |
Regulatory liabilities: |  |
Estimated service lives of assets | 100 years |
Cost of removal |  |
Regulatory liabilities: |  |
Total regulatory liabilities | $ 394,391 | 364,398
Future income tax benefits due to customers |  |
Regulatory liabilities: |  |
Total regulatory liabilities | 82,285 | 84,128
Unrecognized pensions and other postretirement benefits |  |
Regulatory liabilities: |  |
Total regulatory liabilities | 32,996 | 27,872
PFAS Legal Settlement Proceeds |  |
Regulatory liabilities: |  |
Total regulatory liabilities | 24,682 | 0
Employee benefit costs |  |
Regulatory liabilities: |  |
Total regulatory liabilities | 8,771 | 1,137
Revenue adjustment mechanisms |  |
Regulatory liabilities: |  |
Total regulatory liabilities | 0 | 1,122
Water supply costs |  |
Regulatory liabilities: |  |
Total regulatory liabilities | 0 | 3,386
Other |  |
Regulatory liabilities: |  |
Total regulatory liabilities | 3,672 | 2,798
Future income tax benefits due to customers |  |
Regulatory assets: |  |
Total regulatory assets | 204,384 | 180,103
MWRAM |  |
Regulatory assets: |  |
Total regulatory assets | 8,553 | 9,985
Business combinations debt premium |  |
Regulatory assets: |  |
Total regulatory assets | 9,772 | 12,313
Employee benefit costs |  |
Regulatory assets: |  |
Total regulatory assets | 5,823 | 6,370
Catastrophic event memorandum accounts (“CEMA”) |  |
Regulatory assets: |  |
Total regulatory assets | 127 | 986
Revenue adjustment mechanisms |  |
Regulatory assets: |  |
Total regulatory assets | 7,931 | 5,024
Customer Assistance Program (“CAP”) balancing account |  |
Regulatory assets: |  |
Total regulatory assets | 3,696 | 6,599
Water supply costs |  |
Regulatory assets: |  |
Total regulatory assets | 847 | 0
Unrecognized pensions and other postretirement benefits |  |
Regulatory assets: |  |
Total regulatory assets | 0 | 3,177
2022 general rate case interim memorandum account |  |
Regulatory assets: |  |
Total regulatory assets | 0 | 3,392
Other |  |
Regulatory assets: |  |
Total regulatory assets | $ 13,729 | $ 14,278

X
- Definition Net Regulatory Liabilities + References No definition available. + Details
Name: | hto_NetRegulatoryLiabilitiesAbstract
Namespace Prefix: | hto_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_NetRegulatoryAssetsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Useful life of assets common to business units owned by public utility, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesPropertyPlantAndEquipmentCommonUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 980 -SubTopic 340 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478742/980-340-50-1 + Details
Name: | us-gaap_RegulatoryAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are expected to be recovered through revenue sources within one year or the normal operating cycle, if longer. Such costs are capitalized if they meet both of the following criteria: a. It is probable that future revenue in an amount at least equal to the capitalized cost will result from inclusion of that cost in allowable costs for rate-making purposes. b. Based on available evidence, the future revenue will be provided to permit recovery of the previously incurred cost rather than to provide for expected levels of similar future costs. If the revenue will be provided through an automatic rate-adjustment clause, this criterion requires that the regulator's intent clearly be to permit recovery of the previously incurred cost. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 980 -SubTopic 340 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478742/980-340-50-1 + Details
Name: | us-gaap_RegulatoryAssetsCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 980 -SubTopic 340 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478742/980-340-50-1 + Details
Name: | us-gaap_RegulatoryAssetsNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 980 -SubTopic 405 -Name Accounting Standards Codification -Section 25 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477571/980-405-25-1 + Details
Name: | us-gaap_RegulatoryLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount for the individual regulatory current liability as itemized in a table of regulatory current liabilities as of the end of the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 980 -SubTopic 405 -Name Accounting Standards Codification -Section 25 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477571/980-405-25-1 + Details
Name: | us-gaap_RegulatoryLiabilityCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount for the individual regulatory noncurrent liability as itemized in a table of regulatory noncurrent liabilities as of the end of the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(24)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_RegulatoryLiabilityNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=hto_CostOfRemovalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=us-gaap_DeferredIncomeTaxChargesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=hto_UnrecognizedPensionsAndOtherPostretirementBenefitsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=hto_PFASLegalSettlementProceedsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=hto_EmployeeBenefitCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=hto_RevenueAdjustmentMechanismsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=hto_WaterSupplyCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=hto_OtherRegulatoryLiabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=us-gaap_DeferredIncomeTaxChargesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=hto_MontereyWaterRevenueAdjustmentMechanismMWRAMMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=hto_BusinessCombinationsDebtPremiumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=hto_EmployeeBenefitCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=hto_CatastrophicEventMemorandumAccountsCEMAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=hto_RevenueAdjustmentMechanismsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=hto_CustomerAssistanceProgramBalancingAccountMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=hto_WaterSupplyCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=us-gaap_PensionAndOtherPostretirementPlansCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=hto_A2022GeneralRateCaseInterimMemorandumAccountMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=hto_OtherRegulatoryAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |