When Does a Dam Need a Permit in Virginia?
The threshold question in Virginia is whether the dam is regulated at all, and the answer turns on a size test paired with a consequence test. Both are below, from Va. Code §§ 10.1-604 et seq. and Virginia Impounding Structure Regulations, 4VAC50-20.
What counts as an impounding structure
Virginia's threshold in § 10.1-604 is two-pronged, and the second prong is the one that surprises people:
| Prong | Height | Capacity |
|---|---|---|
| 1 | 25 feet or more | and 15 acre-feet or more |
| 2 | 6 feet or more | and 50 acre-feet or more |
The second prong catches broad, shallow impoundments that no height-based rule of thumb would flag. A 7-foot dam holding 60 acre-feet is an impounding structure in Virginia. The same structure is comfortably below the first-look thresholds in most neighbouring states.
Exclusions
- Structures licensed by the State Corporation Commission that have a safety inspection programme.
- Structures owned or operated by the United States government.
- Agricultural structures less than 25 feet high or creating less than 100 acre-feet.
- Water or silt retaining structures approved under mining regulations.
- Obstructions in a canal used to raise or lower water.
Certificates rather than one-off permits
Virginia runs an operation-and-maintenance certificate system under 4VAC50-20 rather than a single construction permit. High and significant hazard structures hold a Regular Operation and Maintenance Certificate, or a Conditional certificate where deficiencies exist; low hazard structures hold a General or Conditional General permit. The certificate is a continuing authorisation, so a lapse is a compliance problem in itself.
Recent amendments. Acts 2025, cc. 228 and 241 amended multiple sections of the Act, including definitions, hazard classification procedures and enforcement. Any summary of Virginia dam law written before 2025 should be treated as suspect.
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.