Dam safety by state

Virginia Dam Safety Requirements

By Michael Flynn, PE · water resources & dam safety engineer

What the Dam Safety Act and Virginia Impounding Structure Regulations, 4VAC50-20 actually require of a dam owner in Virginia — which dams are regulated, how they are classified, when approval is needed, and who has to file an emergency action plan. Every requirement tied to the statute or rule that imposes it.

The short version

Virginia regulates dams under Va. Code §§ 10.1-604 et seq. (Dam Safety Act) and Virginia Impounding Structure Regulations, 4VAC50-20, administered by the Virginia Soil and Water Conservation Board, administered by the Department of Conservation and Recreation (DCR).

Virginia can regulate a six-foot dam, and puts a number on what counts as a major roadway: more than 400 vehicles AADT.

Virginia by the numbers

Virginia dam inventory — NID extract 2026-8-28
MeasureCount
Total dams2,712
High hazard452
— with no EAP recorded37 (8.2%)
High hazard rated Poor59
High hazard rated Unsatisfactory7

The three things an owner has to get right

1. Is the dam regulated?

The threshold test, the exemptions, and the approvals needed to build, repair, alter or remove. Permits and exemptions →

2. What is its hazard classification?

Classification turns on downstream consequence rather than dam size, and it drives design criteria and filing duties alike. Classification criteria →

3. Does it need an emergency action plan?

Who must file, when, and what the recurring duty is. EAP requirements →

Dams by county

Virginia dams by county — NID extract 2026-8-28
CountyDamsHigh hazardPoor/Unsat.
Albemarle1642110
Loudoun98164
Bedford97133
Hanover9141
Goochland8852
Pittsylvania8773
Caroline81612
Fauquier8084
Chesterfield76111
Fairfax75291
Powhatan7124
Halifax6301
Hazard Classification
Screen downstream consequence
Dam Breach Peak Discharge
Failure hydrograph for inundation mapping
National EAP Gap Data
Where Virginia sits nationally

Scope. General information about Virginia dam safety regulation, read from primary sources and current as of 2026-08-28. Not an engineering opinion about any specific structure and not legal advice. Requirements change when the legislature amends the Dam Safety Act or the rules are revised — confirm against the current text of Va. Code §§ 10.1-604 et seq. and Virginia Impounding Structure Regulations, 4VAC50-20, and contact the Virginia Soil and Water Conservation Board for a determination that binds.

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