Hudson, NH Environmental Rules: Flood Zones (2026)

Hudson's Flood Damage Prevention chapter, adopted in 1987 by Ord. No. O87-5, makes the Town a participating community in the National Flood Insurance Program under § 218-1, which applies to lands designated as special flood hazard areas on FEMA's Flood Insurance Rate Map for Hillsborough County, dated September 25, 2009, as amended. The chapter overlays and supplements Hudson's Zoning Ordinance, and where the two conflict, the more restrictive standard controls. Section 218-3 requires a floodplain permit, issued by the Town Engineer, for all proposed development in a special flood hazard area.

Under § 218-4, the Town Engineer determines the base flood elevation for each site, using FEMA's Flood Insurance Study data in Zone AE or, in Zone A, the best available data or at least two feet above the highest adjacent grade if no data exists. Section 218-4E then requires new construction and substantial improvements of residential structures to have their lowest floor, including any basement, elevated to or above that base flood elevation; nonresidential structures must either meet the same elevation or be certified watertight and floodproofed by a licensed engineer or architect.

Manufactured homes placed in a flood hazard area must be elevated on a permanent foundation and anchored against flotation and lateral movement. Appeals and variance requests go to a Joint Committee of the Zoning Board of Adjustment and Building Board of Appeals under § 218-8, which weighs flood danger, alternative sites and community impact before granting relief, with further appeal available to Superior Court.