How building permits work in New Hampshire
These rules apply across New Hampshire. Each local guide above covers what is specific to that city or county: its building department and contacts, permit types, fees and inspections.
One state code, local enforcement and the state permits
New Hampshire applies one code everywhere and leaves the enforcing to the town. Under RSA 155-A all buildings, building components and structures constructed in New Hampshire must comply with the state building code and the state fire code — there is no opting out of the standard. What varies is who administers it: a municipality takes on permitting and inspection only by adopting an enforcement mechanism under RSA 155-A:3, and not every town has done so. The code itself is the 2024 international building, residential, existing building, plumbing, mechanical and swimming pool codes with the 2018 energy code and the 2023 National Electrical Code, all with New Hampshire amendments, in force since the first of July 2026.
Two statutory rules shape every New Hampshire project and neither is in the model code. The first is a lock on the edition: the state building code in effect when the permit application is received by the governing authority remains in effect for the duration of the work covered by that permit, so a long project is not overtaken mid-build by a new code. The second is the concurrency period: for six months after a new edition takes effect an applicant may elect to show compliance under either the old code or the new one — but not a combination of the two. Because the 2024 codes took effect on the first of July 2026, an applicant may still choose the 2021 codes until the end of 2026. Beyond that, the code governs construction, alteration, renovation, rehabilitation, repair, removal and demolition; the adopted codes excuse ordinary repairs from a permit, but the work must still meet the code.
What the municipality may change, and what it may not
New Hampshire lets a municipality amend the state building code only on administrative matters, and then puts a check on it. Under RSA 155-A:3 a town may set its own permit process, fees and certificates of occupancy, but it may not change the technical requirements of the code. A local amendment cannot be enforced until the state Building Code Review Board has confirmed it, and the board publishes the amendments it confirms. A municipality that has adopted an enforcement mechanism may contract the work to a local enforcement agency or a qualified third party rather than employ its own building official, and that contractor has the same authority as a building official. Appeals from a local building official go to the town’s building code board of appeals, and from there to the Building Code Review Board within 30 days; where the zoning board or the selectmen act as the appeals board, they hear only appeals about local amendments. Appeals from the State Fire Marshal also go to the Building Code Review Board.
The state permits that sit outside the town
Several New Hampshire approvals come from the state rather than the municipality, and they are the ones most often missed. The Shoreland Water Quality Protection Act requires a permit from the Department of Environmental Services for construction, excavation and filling within 250 feet of a protected water body — a state permit, not a local ordinance. Wetlands work and subsurface sewage approval run through the same department. The State Fire Marshal permits, inspects and certifies buildings owned by the state, the university system and the community college system wherever they stand, and enforces the code in a municipality without its own enforcement mechanism that has asked for help in writing.
Contractor duties and trade licences
New Hampshire issues no general contractor licence. A builder needs no state credential to take on a house, and the statute puts the duty squarely on them anyway: the contractor is responsible for meeting the minimum requirements of the state building code and state fire code, and no municipality may be held liable for a contractor’s failure to comply. The trades are licensed through the Office of Professional Licensure and Certification: electricians under the electricians’ board (RSA 319-C), and plumbers and gas fitters by the mechanical licensing board (RSA 153:27 to 153:36). The licence is needed whether or not the town enforces the code, though a homeowner may do electrical, plumbing and gas work on a single-family home they own and live in.
Trade work follows the town’s permit process where the town enforces, and is done by tradespeople holding the state licence their trade requires. New Hampshire declines to enforce arc-fault protection beyond the 2014 electrical requirements, whichever edition of the electrical code the state has adopted.