Herndon, VA Environmental Rules: Flood Zones (2026)

Herndon participates in the National Flood Insurance Program (NFIP) and enforces floodplain development through the Town Floodplain Management Ordinance (Chapter 78). FEMA Flood Insurance Rate Maps (FIRMs) for Fairfax County identify Special Flood Hazard Areas (Zone AE primarily) along Sugarland Run, Horsepen Creek, and their tributaries. Any development within the SFHA, including new construction, substantial improvements (50% or more of pre-improvement market value), fill, grading, or utility installation, requires a Floodplain Development Permit from the Town Floodplain Administrator. New residential structures must have the lowest floor (including basement) elevated at least 2 feet above the Base Flood Elevation (BFE) per Herndon's freeboard requirement, which exceeds the federal 1-foot minimum. Non-residential structures may be dry-floodproofed to BFE plus 2 feet. An Elevation Certificate prepared by a Virginia-licensed surveyor, engineer, or architect is required at both permit issuance and post-construction. The floodway, which is the central channel area, is off-limits to fill or development that would increase flood heights by any measurable amount. Manufactured homes, fuel tanks, and mechanical equipment (HVAC, water heaters) must be elevated above BFE plus freeboard. Substantial damage determinations are made by the Town; if damage to a structure is 50% or more of market value, the structure must be brought into full compliance including elevation. Federally-backed mortgages on properties in SFHAs require flood insurance under the Flood Disaster Protection Act. Violations can result in loss of NFIP eligibility for the community and significant fines. Herndon may participate in the Community Rating System (CRS) which provides flood insurance discounts to residents.