Dam Safety Regulation by State
Dam safety is regulated state by state, and the requirements differ everywhere — what counts as a jurisdictional dam, how hazard is classified, who must file an emergency action plan, and what triggers a permit. This section pairs the governing statute and rule for each state with inventory data computed from the National Inventory of Dams.
North Carolina — full treatment: hazard classification, permits and exemptions, emergency action plans, and county-level inventory.
Additional states are being added only as each one's requirements are verified against current primary sources. Inventory data is available nationally now; regulatory summaries are published per state as they are checked.
High-hazard dams by state
A high-hazard classification means failure would likely cause loss of life. It is a statement about what is downstream, not about the size or condition of the dam. Nationally there are 17,049 high-hazard dams out of 92,766.
| State | Total dams | High hazard | Share |
|---|---|---|---|
| North Carolina | 3,687 | 1,678 | 45.5% |
| Texas | 7,421 | 1,648 | 22.2% |
| Missouri | 5,385 | 1,478 | 27.4% |
| California | 1,534 | 877 | 57.2% |
| Pennsylvania | 1,492 | 788 | 52.8% |
| South Carolina | 2,440 | 679 | 27.8% |
| Georgia | 5,412 | 556 | 10.3% |
| Colorado | 1,984 | 474 | 23.9% |
| Virginia | 2,712 | 452 | 16.7% |
| New York | 1,941 | 451 | 23.2% |
North Carolina leads the country in high-hazard dams despite ranking eighth in total dam count — a consequence of dense downstream development around impoundments built for recreation and water supply in the mid-20th century. North Carolina requirements →
Compare states side by side
Four adjacent southeastern states, four different answers to the same three questions. South Carolina's size exemption is conjunctive where North Carolina's is disjunctive; Georgia has no middle hazard tier at all; Virginia can regulate a six-foot dam and requires its emergency action plans to be public. NC, SC, GA and VA compared →
National data
Of the high-hazard dams in the United States — structures whose failure would likely cause loss of life — a substantial share have no emergency action plan on record. The gap, ranked by state, with a downloadable CSV →
Worked examples
Four problems worked end to end on one structure — a breach analysis that produces a flood rise, a flood rise that decides a hazard classification, a classification that decides whether a size exemption survives, and a classification that sets the spillway design flood. Dam safety worked examples →
Why state rules differ so much
There is no federal dam safety code for non-federal dams. FEMA publishes guidance (P-93 on hazard classification, P-94 on selecting design floods) and administers the National Dam Safety Program, but the binding requirements are state law. That means the same physical structure can be jurisdictional in one state and exempt across the line, and that an engineer working in multiple states cannot carry assumptions between them.
Data source. Dam counts, hazard classifications, condition ratings and EAP status are computed directly from the U.S. Army Corps of Engineers National Inventory of Dams national extract, stamped 2026-8-28. NID reflects what state and federal programs have reported to USACE; it can lag a state program's own records, and an "EAP Prepared: No" flag means no plan is recorded in NID rather than proof that no plan exists. Figures here are computed from the raw extract, not quoted from secondary reporting.
On regulatory summaries. State summaries here are written from current primary sources — the statute and administrative code as published by the state — and each carries the date it was last verified. Secondary compilations of state dam safety law go stale quickly; several widely cited ones predate amendments now in force. Where a state has not yet been verified, this site publishes inventory data and the governing citation rather than a paraphrase of requirements.