Nashua, NH Environmental Rules: Flood Zones (2026)
FEMA flood zone rules in Nashua, NH, also called floodplain regulations or special flood hazard area (SFHA) rules, determine flood insurance requirements and elevation standards for new construction.
Key Facts
- Enforced by
- Department of Building Safety
- Residential elevation
- 1 ft above base flood elevation
- Permit required
- in any special flood hazard area
- Floodway rule
- no development raising flood levels
- Adopted under
- RSA 674:16
Summary
Nashua requires a permit for any development in a FEMA-mapped special flood hazard area, and new construction or substantial improvement of a residential structure must have its lowest floor at least one foot above the 100-year flood elevation.
The Department of Building Safety shall review all building permit applications for new construction or substantial improvements to determine whether proposed building sites will be reasonably safe from flooding. If a proposed building site is located in a special flood hazard area, all development shall:
A. Be designed (or modified) and adequately anchored to prevent floatation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;
B. Be constructed with materials resistant to flood damage;
C. Be constructed by methods and practices that minimize flood damages;
D. All nonresidential development: be constructed with electrical, heating, ventilation, plumbing, and air conditioning equipment, and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding; and
E. All residential development, including new construction, placements of new manufactured homes, and substantial improvements, be constructed with electrical, heating, ventilation, plumbing, and air conditioning equipment, and other service facilities that are located at least one foot above base flood elevation so as to prevent water from entering or accumulating within the components during conditions of flooding.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4805762; v29 updated 2026-02-10; through 02-10-2026).
Full Breakdown
Adopted under RSA 674:16 as the City of Nashua Floodplain Development Ordinance (Zoning Ordinance Ch. 190, Art. VII), the rule applies wherever FEMA's Flood Insurance Rate Maps designate Zone A, AE or AO. The Department of Building Safety reviews every building permit application for flood safety; § 190-66 bars issuing a permit until other required federal or state approvals are on file. § 190-68 sets the elevation standard, one foot above base flood elevation for residential lowest floors, and along a designated regulatory floodway § 190-67 forbids any fill or new construction that would raise flood levels during the base flood discharge. Variances go to the Zoning Board of Adjustment under § 190-70.
Violations & Fines
Development lacking a required elevation certificate or other compliance documentation is presumed a violation under § 190-62. The Administrative Officer/Department of Building Safety withholds permits until federal, state and local flood-hazard approvals are shown; noncompliant structures also risk higher flood-insurance premiums.
Frequently Asked Questions
Do I need a permit to build in a Nashua flood zone?
How high must a new Nashua home be built in a flood zone?
Sources & Official References
Other rules in Nashua
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Flood Zones in Nearby Cities
How other cities in this county handle flood zones.