High-Hazard Dams by ZIP Code

Source period August 2026. Recomputed by ZipCheckup from the cited federal source.

17,046 dams across 50 states carry a high hazard-potential rating — failure would probably cause loss of life — and 2,788 are rated in poor or unsatisfactory condition, as of August 2026.

By state

We report two independent facts side by side and do not rank states. A larger count reflects the size of a state's inventory and its reporting activity, not a judgment about water safety.

How we compute this

We use the USACE National Inventory of Dams, the federal register of the nation's dams, and count those classified as high hazard potential — meaning a failure or misoperation would probably cause loss of human life. As of August 2026 that is 17,046 of 92,756 inventoried dams (18.4%). Hazard potential describes the consequence of a failure, not the probability that one will happen.

Within that high-hazard group we report two safety gaps the inventory records directly: dams whose condition assessment is poor or unsatisfactory (2,788), and dams where an emergency action plan is required but not prepared (2,475). We do not report downstream population, because the public inventory does not publish it.

Figures are grouped by state and recompute on every build. The undetermined hazard class is kept separate, never folded into a lower rating, and a small number of dams on territorial or tribal land are counted in the national totals but not assigned to a state.

Frequently asked questions

@misc{zipcheckup-findings-high-hazard-dams-by-zip,
  author = {{ZipCheckup}},
  title  = {{High-Hazard Dams by ZIP Code}},
  year   = {2026},
  url    = {https://zipcheckup.com/findings/high-hazard-dams-by-zip/}
}