{
  "name": "Dam safety hazard classification, inspection frequency, and owner obligations by US state",
  "description": "State-by-state comparison of dam safety programs: hazard classification systems, inspection frequencies, who must inspect, and dam owner obligations. Each record is one (state, hazard class) pair with the classification name, criteria for that class, required inspection interval, inspector qualifications, and whether inspections are mandatory or voluntary. Covers the ~91,000 non-federal dams in the US. Answers 'how often must my dam be inspected in [state]', 'what hazard classification is my dam', 'do I need a licensed engineer for inspections in [state]', and 'what are the penalties for non-compliance'. The ASDSO published a 50-state summary in 2020 as a PDF; it is now 6 years stale and not structured for search. This asset maintains the current state of each program from each state's own dam safety statute and program pages.",
  "url": "https://referencesource.org/state-dam-safety-classification/",
  "licence": "US state government works \u2014 public domain",
  "last_verified": "2026-08-16",
  "stale_after": "2027-08-16",
  "sources": [
    "https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/All-Programs/Division-of-Safety-of-Dams/Files/Publications/Division-of-Safety-of-Dams-Definitions-for-Downstream-Hazard-and-Condition-Assessment.pdf",
    "https://www.michigan.gov/egle/about/organization/water-resources/dam-safety/rules-regs",
    "https://dec.vermont.gov/water-investment/dam-safety/inspection-program"
  ],
  "records": [
    {
      "state": "California",
      "hazard_class": "Extremely High",
      "classification_criteria": "Expected to cause considerable loss of human life or would result in an inundation area with a population of 1,000 or more.",
      "inspection_frequency": "annually",
      "inspection_mandatory": "yes",
      "inspector_qualification": "Division of Safety of Dams (DSOD)",
      "statute_citation": "California Water Code",
      "id": "extremely-high-california",
      "url": "https://referencesource.org/state-dam-safety-classification/extremely-high-california/",
      "source": "https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/All-Programs/Division-of-Safety-of-Dams/Files/Publications/Division-of-Safety-of-Dams-Definitions-for-Downstream-Hazard-and-Condition-Assessment.pdf",
      "source_quote": "Expected to cause considerable loss of human life or would result in an"
    },
    {
      "state": "California",
      "hazard_class": "High",
      "classification_criteria": "Expected to cause loss of at least one human life.",
      "inspection_frequency": "annually",
      "inspection_mandatory": "yes",
      "inspector_qualification": "Division of Safety of Dams (DSOD)",
      "statute_citation": "California Water Code",
      "id": "high-california",
      "url": "https://referencesource.org/state-dam-safety-classification/high-california/",
      "source": "https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/All-Programs/Division-of-Safety-of-Dams/Files/Publications/Division-of-Safety-of-Dams-Definitions-for-Downstream-Hazard-and-Condition-Assessment.pdf",
      "source_quote": "Expected to cause loss of at least one human life.",
      "verified_fields": [
        "classification_criteria"
      ]
    },
    {
      "state": "Michigan",
      "hazard_class": "High",
      "classification_criteria": "Emergency Action Plans (EAPs) are required for high and significant hazard dams",
      "inspection_frequency": "every 3 years",
      "inspection_mandatory": "yes",
      "inspector_qualification": "professional engineer licensed in Michigan",
      "statute_citation": "Part 315, Dam Safety, Natural Resources and Environmental Protection Act, 1994 PA 451",
      "id": "high-michigan",
      "url": "https://referencesource.org/state-dam-safety-classification/high-michigan/",
      "source": "https://www.michigan.gov/egle/about/organization/water-resources/dam-safety/rules-regs",
      "source_quote": "High hazard dams require an inspection report to be submitted every three years. Inspection reports must be prepared, signed, and sealed by a professional engineer licensed in Michigan.",
      "verified_fields": [
        "hazard_class",
        "inspector_qualification",
        "state"
      ]
    },
    {
      "state": "Vermont",
      "hazard_class": "High",
      "classification_criteria": "Probable or Certain (one or more) (extensive downstream residential, commercial, or industrial development)",
      "inspection_frequency": "2 years",
      "inspection_mandatory": "no",
      "inspector_qualification": "Dam Safety Program or an engineer hired by the Owner",
      "statute_citation": "10 V.S.A. \u00a7 1105",
      "id": "high-vermont",
      "url": "https://referencesource.org/state-dam-safety-classification/high-vermont/",
      "source": "https://dec.vermont.gov/water-investment/dam-safety/inspection-program",
      "source_quote": "High | Probable or Certain (one or more) (extensive downstream residential, commercial, or industrial development) | Not considered for this classification | Not considered for this classification | Not considered for this classification | 2 years",
      "verified_fields": [
        "classification_criteria",
        "hazard_class",
        "inspection_frequency"
      ]
    },
    {
      "state": "California",
      "hazard_class": "Low",
      "classification_criteria": "No probable loss of human life and low economic and environmental losses. Losses are expected to be principally limited to the owner's property.",
      "inspection_frequency": "annually",
      "inspection_mandatory": "yes",
      "inspector_qualification": "Division of Safety of Dams (DSOD)",
      "statute_citation": "California Water Code",
      "id": "low-california",
      "url": "https://referencesource.org/state-dam-safety-classification/low-california/",
      "source": "https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/All-Programs/Division-of-Safety-of-Dams/Files/Publications/Division-of-Safety-of-Dams-Definitions-for-Downstream-Hazard-and-Condition-Assessment.pdf",
      "source_quote": "No probable loss of human life and low economic and environmental losses.",
      "verified_fields": [
        "hazard_class"
      ]
    },
    {
      "state": "Michigan",
      "hazard_class": "Low",
      "classification_criteria": "Dams that are over six feet in height and impound five acres or more",
      "inspection_frequency": "every 5 years",
      "inspection_mandatory": "yes",
      "inspector_qualification": "professional engineer licensed in Michigan",
      "statute_citation": "Part 315, Dam Safety, Natural Resources and Environmental Protection Act, 1994 PA 451",
      "id": "low-michigan",
      "url": "https://referencesource.org/state-dam-safety-classification/low-michigan/",
      "source": "https://www.michigan.gov/egle/about/organization/water-resources/dam-safety/rules-regs",
      "source_quote": "Low hazard dams require an inspection report to be submitted every five years.",
      "verified_fields": [
        "hazard_class"
      ]
    },
    {
      "state": "Vermont",
      "hazard_class": "Low",
      "classification_criteria": "None Expected loss of life; Private agricultural lands, equipment and isolated non-occupied buildings, non-major roads; No disruption of services \u2013 repairs are cosmetic or rapidly repairable damage; Minimal incremental damage",
      "inspection_frequency": "10 years",
      "inspection_mandatory": "no",
      "inspector_qualification": "Dam Safety Program or an engineer hired by the Owner",
      "statute_citation": "10 V.S.A. \u00a7 1105",
      "id": "low-vermont",
      "url": "https://referencesource.org/state-dam-safety-classification/low-vermont/",
      "source": "https://dec.vermont.gov/water-investment/dam-safety/inspection-program",
      "source_quote": "Low | None Expected | Private agricultural lands, equipment and isolated non-occupied buildings, non-major roads | No disruption of services \u2013 repairs are cosmetic or rapidly repairable damage | Minimal incremental damage | 10 years",
      "verified_fields": [
        "classification_criteria",
        "hazard_class",
        "inspection_frequency",
        "inspection_mandatory"
      ]
    },
    {
      "state": "Vermont",
      "hazard_class": "Minimal",
      "classification_criteria": "Same as LOW hazard; None property losses",
      "inspection_frequency": "10 years",
      "inspection_mandatory": "no",
      "inspector_qualification": "Dam Safety Program or an engineer hired by the Owner",
      "statute_citation": "10 V.S.A. \u00a7 1105",
      "id": "minimal-vermont",
      "url": "https://referencesource.org/state-dam-safety-classification/minimal-vermont/",
      "source": "https://dec.vermont.gov/water-investment/dam-safety/inspection-program",
      "source_quote": "Minimal | Same as LOW hazard | None",
      "verified_fields": [
        "hazard_class"
      ]
    },
    {
      "state": "California",
      "hazard_class": "Significant",
      "classification_criteria": "No probable loss of human life but can cause economic loss, environmental damage, impacts to critical facilities, or other significant impacts.",
      "inspection_frequency": "annually",
      "inspection_mandatory": "yes",
      "inspector_qualification": "Division of Safety of Dams (DSOD)",
      "statute_citation": "California Water Code",
      "id": "significant-california",
      "url": "https://referencesource.org/state-dam-safety-classification/significant-california/",
      "source": "https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/All-Programs/Division-of-Safety-of-Dams/Files/Publications/Division-of-Safety-of-Dams-Definitions-for-Downstream-Hazard-and-Condition-Assessment.pdf",
      "source_quote": "No probable loss of human life but can cause economic loss, environmental"
    },
    {
      "state": "Michigan",
      "hazard_class": "Significant",
      "classification_criteria": "Emergency Action Plans (EAPs) are required for high and significant hazard dams",
      "inspection_frequency": "every 4 years",
      "inspection_mandatory": "yes",
      "inspector_qualification": "professional engineer licensed in Michigan",
      "statute_citation": "Part 315, Dam Safety, Natural Resources and Environmental Protection Act, 1994 PA 451",
      "id": "significant-michigan",
      "url": "https://referencesource.org/state-dam-safety-classification/significant-michigan/",
      "source": "https://www.michigan.gov/egle/about/organization/water-resources/dam-safety/rules-regs",
      "source_quote": "Significant hazard dams require an inspection report to be submitted every four years.",
      "verified_fields": [
        "hazard_class"
      ]
    },
    {
      "state": "Vermont",
      "hazard_class": "Significant",
      "classification_criteria": "None expected loss of life; Major or extensive public and private facilities property losses; Disruption of essential or critical facilities and access; Major or extensive mitigation required or impossible to mitigate",
      "inspection_frequency": "5 years",
      "inspection_mandatory": "no",
      "inspector_qualification": "Dam Safety Program or an engineer hired by the Owner",
      "statute_citation": "10 V.S.A. \u00a7 1105",
      "id": "significant-vermont",
      "url": "https://referencesource.org/state-dam-safety-classification/significant-vermont/",
      "source": "https://dec.vermont.gov/water-investment/dam-safety/inspection-program",
      "source_quote": "Significant | None expected | Major or extensive public and private facilities | Disruption of essential or critical facilities and access | Major or extensive mitigation required or impossible to mitigate | 5 years",
      "verified_fields": [
        "hazard_class",
        "inspection_frequency"
      ]
    }
  ]
}