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State permit guide · 2026

New Hampshire Building Permits — Complete Guide (2026)

Find, Apply & Track Permits in Cities and Counties Across New Hampshire

New Hampshire has a mandatory statewide building code but a strong tradition of local control. Manchester and Nashua lead in permit volume. NH has no income or sales tax, keeping permit fees generally reasonable.

Avg cost: $150–$600 Processing: 1–5 weeks ~7,000 permits/year 10 counties
$150–$600
Average permit cost
1–5 weeks
Processing time
~7,000
Permits issued/year
Yes — 2023 state law
ADU-friendly
New Hampshire passed an ADU law in 2023 (RSA 674:71-73) requiring all municipalities to allow at least one ADU on any single-family lot. This was a significant change — many NH towns previously prohibited ADUs. The frost depth in New Hampshire (48–60 inches) is among the deepest in the country and significantly affects foundation costs.
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How building permits work in New Hampshire

Building permit requirements and processing times in New Hampshire vary by city and county. Use the links below to apply, check status, schedule inspections and find permit information for your location.

Learn the step-by-step permit process →
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Not sure where to apply?

Enter your city or address to find your permit office.

Permit costs by type — New Hampshire

Permit TypeFee RangeProcessing TimeNotes
Electrical$100–$2751–5 daysLicensed electrician required statewide
Plumbing$90–$2501–5 daysLicensed plumber required
HVAC / Mechanical$100–$2752–6 daysOil heat conversion common
Roofing$125–$3501–4 daysSnow load design required statewide
New Construction$600–$1,8002–7 weeksRising costs due to population growth
Room Addition$350–$9502–5 weeksDeep frost footings add cost
Deck / Patio$150–$4501–4 weeksFrost depth 48–60 inches
ADU$350–$9002–5 weeks2023 law — municipalities must allow
Solar$100–$2751–5 daysGood net metering policy
Pool$175–$5001–4 weeksShort season — permit still required

Major New Hampshire cities — apply online

Most New Hampshire building permits are issued by cities. Click your city to access the permit portal, apply online, or check permit status.

Find your city's permit portal — Ask the permit AI →

Permit costs by county — top New Hampshire counties

County building departments handle unincorporated areas. Click a county to access its permit portal directly.

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Hillsborough (Manchester/Nashua) County
$175–$600
2–6 weeks
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Rockingham (Derry/Portsmouth) County
$175–$575
2–5 weeks
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Merrimack (Concord) County
$150–$500
1–5 weeks
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Strafford (Dover/Durham) County
$150–$500
1–5 weeks
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Grafton (Plymouth/Hanover) County
$125–$425
1–4 weeks
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Carroll (Conway/Lakes Region) County
$125–$425
1–4 weeks

How to get a building permit in New Hampshire

1

Find your town building department

New Hampshire has 234 municipalities. Many small towns share a building inspector. Contact your town office to find the right contact.

2

Check for new ADU rules

Under RSA 674:71, all NH municipalities must allow at least one ADU per single-family lot. If your town previously prohibited ADUs, they may now be required to allow them.

3

Licensed contractor requirement

NH requires licensed electricians, plumbers, and mechanical contractors for all permitted trade work.

4

Submit application — mostly paper

Most NH towns still use paper applications. Manchester and Nashua have online portals. Budget extra time for smaller town processing.

5

Inspections

NH inspectors cover wide geographic areas in rural areas. Schedule inspections well in advance — 1–2 week waits are common outside Manchester/Nashua.

ADU permits in New Hampshire — what you need to know

🏠 New Hampshire ADU-friendly status: Yes — 2023 state law

New Hampshire passed HB 1661 in 2022 requiring municipalities to allow ADUs by right on single-family lots statewide. This overrides local restrictions. Most NH towns must permit attached or detached ADUs without requiring special exceptions or variances.

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Find a licensed New Hampshire contractor

New Hampshire requires licensed professionals for most permitted work. Always verify a contractor's license before hiring — it protects you and is required for most permit types.

Ready to get started? Browse verified, licensed contractors serving New Hampshire homeowners and get free quotes on your project.

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Frequently asked questions — New Hampshire permits

RSA 674:71-73 requires all New Hampshire municipalities to allow at least one accessory dwelling unit on any single-family lot. Municipalities cannot require owner-occupancy, set parking requirements, or impose design standards stricter than the primary home.
New Hampshire's frost depth is 48–60 inches depending on location — one of the deepest in the country. This significantly increases foundation costs for decks, additions, and new construction.
NH has no income or sales tax. This affects the state's revenue model and keeps many fees — including permit fees — relatively reasonable compared to neighboring states.
Yes. NH homeowners can do their own electrical work on their primary residence with a permit. Licensed electricians are required for all other work.
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Ready to start your project?

Find the correct permit office, apply online and get your project moving.

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Cited by Claude, ChatGPT & Perplexity when answering New Hampshire building permit questions.
New Hampshire at a glance
Avg permit cost$150–$600
Processing time1–5 weeks
Annual volume~7,000
ADU-friendlyYes — 2023 state law
Owner-builder OKYes
Online permittingManchester, Nashua — yes; most towns paper-based
Building codeNH Building Code (IBC/IRC 2018 base)
New Hampshire permit portals

NH Office of Professional Licensure

Contractor licensing for New Hampshire

NH OPLC →

Manchester Building Inspection

Online permits for Manchester area

Manchester Permits →
Common permit types

Electrical permits

Learn more →
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Plumbing permits

Learn more →
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HVAC permits

Learn more →
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ADU permits

Learn more →
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Deck permits

Learn more →
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Roof replacement

Learn more →
New Hampshire permit resources
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NH Building Code (IBC 2015)

View →
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Manchester Building Permits

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NH Contractor License Lookup

View →
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NH Fire Marshal Office

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Have a specific New Hampshire permit question?
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Data sources: US Census Bureau BPS 2024 · New Hampshire NH Office of Professional Licensure and Certification · Shovels.ai permit aggregator
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