Dam Hazard Classifications
Loss of Life Expected
Failure would probably cause loss of human life. These dams require the most frequent inspections and must have emergency action plans.
Economic Damage Expected
Failure could cause significant economic damage — flooding roads, bridges, or property — but no expected loss of life.
Minimal Damage Expected
Failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life.
Know Your Dams
Safety Ratings
Every dam is classified by hazard potential and condition assessment. See which dams near you carry the highest risk.
Emergency Plans
High hazard dams are required to have emergency action plans. Find out which dams in your area have one — and which don't.
Inspection History
Dam inspections determine structural safety. See when each dam was last inspected and identify overdue inspections.
Dam Infrastructure
Heights, lengths, storage capacity, dam types, ownership, and construction dates for every dam in the national inventory.
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Explore Dam Records
Oldest Dams
Dams dating back to the 1600s — centuries of American infrastructure.
Tallest Dams
America's highest dams, towering hundreds of feet above their foundations.
Largest Reservoirs
The biggest reservoirs in the U.S., ranked by storage capacity.
High Risk Dams
High hazard dams with poor or unsatisfactory condition ratings.
Understanding Dam Safety Data
Every dam in the National Inventory of Dams receives a hazard potential classification based on the consequences of failure — not the likelihood. A "High" hazard dam is one where failure would probably cause loss of human life. This classification determines inspection frequency, emergency action plan requirements, and regulatory oversight.
Condition assessments rate the physical state of the dam: Satisfactory means no deficiencies recognized, Fair means minor issues being addressed, Poor means recognized deficiencies requiring remediation, and Unsatisfactory means serious deficiencies requiring immediate attention.
DamLookup.com makes this public safety data searchable by address, state, and county so you can understand the dam infrastructure near you.