Building permits, zoning and septic rules across New Hampshire

At a glance

Residential building permits

0 counties with none; 3 limited; 7 required in unincorporated areas⁷²¹

Who issues building permits

The town or city where it enforces the state code; the state system leaves one- and two-family homes out where a town has no enforcement⁴⁸

County-wide zoning

5 counties have none, 5 have county zoning; towns zone locally⁵⁹¹⁰

No building permit and no zoning

0 counties meet both descriptions¹¹

Septic permits

NHDES approves plans in all 10 counties; local plan approval may also apply¹²⁶¹³

RV and tiny-home living

No county-level answer in any of 10 counties; ask the town¹⁴¹⁵

Owner-builder

Conditional plumbing exemption; no statewide exemption from permits or inspections¹⁶⁸

Private wells

Contractor files a completion record within 90 days¹⁷

Who to call

Contact details are copied from each office’s official page and were checked against it on October 13, 2026.

Which New Hampshire counties don't require a building permit?

None. New Hampshire has 0 counties with a blanket no-residential-building-permit answer, 3 with limited requirements and 7 where unincorporated land needs a residential building permit.⁷²¹ The limited group is Grafton County, Sullivan County and Strafford County; limited means a permit applies only in some cases, not a general exemption.² The best-scoring counties that require one are Carroll County, Coos County and Cheshire County.¹

Owner-builders get a conditional plumbing-license exemption, not a statewide exemption from building permits or inspections; the owner-builder county list is a starting point.¹⁶⁸ County lines matter less here than the town: the building permit process depends on whether the town enforces the state code.⁴

Who issues building permits in New Hampshire, and what do they cost?

Where a town has adopted a local enforcement mechanism for the state building code, the permit follows that town's process, and the building official must approve or deny a completed application within 30 days.¹⁸ Where a town has not, the state building permit system excludes one- and two-family dwellings, so a house there is not permitted through the State Fire Marshal; local requirements may still apply if the town has an ordinance.⁴⁸ The State Fire Marshal's office handles questions about the state system.¹⁹

Under the state system, electrical, plumbing, mechanical and fire-protection work each need a separate permit, and the state's published fee for other structures and uses is $1.00 per gross square foot with a $35 minimum; that schedule excludes one- and two-family dwellings.²⁰ Inspections are requested by the permit holder before work is concealed.²¹ Towns may also require a certificate of occupancy before you use a new building.²²

A county with unincorporated towns or unorganized places may set up its own building-code enforcement or require permits for buildings on leased land there.²³²⁴

Which New Hampshire counties have no zoning?

County-wide zoning is absent in 5 New Hampshire counties: Grafton County, Carroll County, Sullivan County, Cheshire County and Belknap County.⁵ Another 5 have county zoning: Coos County, Hillsborough County, Merrimack County, Strafford County and Rockingham County.⁹ See the no-zoning county list.

State law lets a county adopt zoning only for its unincorporated towns and unorganized places, while towns divide themselves into districts with different rules.²⁵¹⁰ Lot size, setbacks, lot coverage and building height are therefore set by the district, with no statewide number.^26272829

Subdividing also runs through the town: a planning board regulates subdivision only where the municipality has authorized it.³⁰ Ask the town planning office for the parcel's district before you buy.

Who issues septic permits in New Hampshire?

The New Hampshire Department of Environmental Services approves septic plans across all 10 counties, though local plan approval may also be required and inspections can be delegated to qualified municipal officials.¹²¹³ No one may build a structure that will discharge sewage, or a disposal system, without prior DES approval of the plans.⁶

Plans must come from a permitted New Hampshire septic system designer, and you need both an Approval for Construction and an Approval for Operation before use.³¹ A system must pass final inspection before it is covered or put into operation, and tanks must be inspected for sludge and scum often enough to be pumped when the layer reaches one-third of tank depth.³²

A composting or incinerator toilet avoids DES approval only where the structure has no internal plumbing and no supplied water; with plumbing and water, an approved disposal system is required even if the toilet is not connected to it.³³

Can you live in an RV or tiny home on your land in New Hampshire?

We could not confirm a county-level answer on private-land RV living in any of New Hampshire's 10 counties, and none on tiny homes either.¹⁴¹⁵ That gap is neither permission nor prohibition: ask the parcel's town zoning office and building official about RV use, temporary occupancy while you build and any tiny-home structure.

The state's campground rules cover temporary recreational occupancy at campgrounds, not permanent living on your own house lot, and municipalities keep authority to enforce local zoning and health-and-safety rules.³⁴ Any dwelling still falls under the state building code, and zoning is set town by town.³¹⁰

Where are the best counties in New Hampshire for a bolthole?

Grafton County leads the Bolthole Index at 83/100, followed by Carroll County and Sullivan County at 81/100; Grafton and Sullivan have limited building permit requirements, Carroll requires building permits, and none has county-wide zoning.³⁵²¹⁵ Coos County scores 77/100 and requires building permits and has county zoning.³⁵⁹

The median county farmland value is $6,630 per acre; Coos County is lowest at $4,071 per acre, followed by Grafton County at $4,312.³⁶ Those are farmland benchmarks, not asking prices for a building lot. The median county effective property tax rate is 1.95% and the median county bill is $5,796 per year.³⁷

What should you know about water and private wells in New Hampshire?

Domestic wells are exempt from the large-groundwater-withdrawal permit regime, but the contractor must give the Water Well Board a completion record within 90 days after the well is finished.³⁸¹⁷ Open-loop geothermal wells need a separate groundwater discharge permit.¹⁷

Plan water and wastewater together: supplied water and internal plumbing trigger an approved sewage disposal system even with a composting toilet.³³ New Hampshire also generally requires connection to a public sewer within 100 feet, and a town may increase that distance or grant waivers for adequate alternatives, so ask the municipal health office before commissioning septic plans.³⁹

Watch-outs

• No county-wide zoning does not remove town zoning: ask the town planning office for the parcel district.¹⁰
• A limited or absent building permit requirement does not waive septic approval from NHDES.²⁶
• Farm use is presumed allowed only where zoning does not address it, and new or significantly expanded livestock operations may still need a special exception, building permit or site plan review.⁴⁰⁴¹
• Agriculture is not exempt from setbacks, driveway, parking or noise rules; relief comes only by waiver after a local hearing.⁴²
• Short-term rental advertisements must carry the operator's meals and rooms license number.⁴³

Sources

1. Bolthole Index county rulebook, 10 New Hampshire counties, as of October 7, 2026: New Hampshire counties that require a residential building permit in unincorporated areas
2. Bolthole Index county rulebook, 10 New Hampshire counties, as of October 7, 2026: New Hampshire counties that require a residential building permit only in some cases (for example floodplain or certain structures)
3. New Hampshire: RSA 155-A:1 Definitions, quoted and re-checked
4. New Hampshire: Chapter 155-A New Hampshire Building Code, quoted and re-checked
5. Bolthole Index county rulebook, 10 New Hampshire counties, as of October 7, 2026: New Hampshire counties with no county-wide zoning
6. New Hampshire: RSA 485-A:32 Prior Approval; Permits, quoted and re-checked
7. Bolthole Index county rulebook, 10 New Hampshire counties, as of October 7, 2026: New Hampshire counties that do not require a residential building permit in unincorporated areas
8. New Hampshire: RSA 155-A:4 — Permit Required, quoted and re-checked
9. Bolthole Index county rulebook, 10 New Hampshire counties, as of October 7, 2026: New Hampshire counties with county zoning
10. New Hampshire: Section 674:20 Districts, quoted and re-checked
11. Bolthole Index county rulebook, 10 New Hampshire counties, as of October 7, 2026: New Hampshire counties with neither a residential building permit nor county-wide zoning
12. Bolthole Index county rulebook, 10 New Hampshire counties, as of October 7, 2026: Who issues septic permits across New Hampshire's counties: a state agency, a multi-county health district, or the county
13. New Hampshire: RSA 485-A:29 Submission and Approval of Plans and Specifications, quoted and re-checked
14. Bolthole Index county rulebook, 10 New Hampshire counties, as of October 7, 2026: New Hampshire counties' answers on living in an RV on your own land
15. Bolthole Index county rulebook, 10 New Hampshire counties, as of October 7, 2026: New Hampshire counties' answers on living in a tiny home on your own land
16. New Hampshire: RSA 153:36 — Exceptions, quoted and re-checked
17. New Hampshire: RSA 482-B:10 Record of Wells; Monitoring Wells, quoted and re-checked
18. New Hampshire: RSA 155-A:4 Permit Required, quoted and re-checked
19. New Hampshire Office of the State Fire Marshal (firemarshal.dos.nh.gov)
20. New Hampshire: Saf-C 8100 State Building Permit System, quoted and re-checked
21. New Hampshire: Saf-C 8100 State Building Permit System, quoted and re-checked
22. New Hampshire: Saf-C 8100 State Building Permit System, quoted and re-checked
23. New Hampshire: RSA 155-A:1 Definitions, quoted and re-checked
24. New Hampshire: RSA 674:41 Erection of Buildings on Streets; Appeals, quoted and re-checked
25. New Hampshire: RSA 674:16 Grant of Power, quoted and re-checked
26. New Hampshire: gc.nh.gov, quoted and re-checked
27. New Hampshire: gc.nh.gov, quoted and re-checked
28. New Hampshire: gc.nh.gov, quoted and re-checked
29. New Hampshire: gc.nh.gov, quoted and re-checked
30. New Hampshire: RSA 674:35 Power to Regulate Subdivisions, quoted and re-checked
31. New Hampshire Department of Environmental Services — Subsurface Systems Bureau (des.nh.gov)
32. New Hampshire: RSA 485-A:29 Submission and Approval of Plans and Specifications, quoted and re-checked
33. New Hampshire: Env-Wq 1000 Subdivisions and Individual Sewage Disposal Systems, quoted and re-checked
34. New Hampshire: Chapter 216-I Recreational Campgrounds and Camping Parks, quoted and re-checked
35. Bolthole Index county rulebook, 10 New Hampshire counties, as of October 7, 2026: The 8 highest-scoring New Hampshire counties on the Bolthole Index (off-grid and homestead land score out of 100), with each one's building-permit, zoning and septic answers
36. Bolthole Index county rulebook, 10 New Hampshire counties, as of October 7, 2026: Median farmland value per acre across New Hampshire's counties (USDA census, the middle county's value; USD/acre), with the five least expensive counties
37. Bolthole Index county rulebook, 10 New Hampshire counties, as of October 7, 2026: Median of New Hampshire's county effective property tax rates and median county property tax bills
38. New Hampshire water rights and groundwater management: National Agricultural Law Center and Bolthole Index groundwater review
39. New Hampshire: RSA 147:8 Toilets; Drains, quoted and re-checked
40. New Hampshire: RSA 674:32-a Presumption, quoted and re-checked
41. New Hampshire: RSA 674:32-b Existing Agricultural Uses and Activities, quoted and re-checked
42. New Hampshire: RSA 674:32-c — Other General Provisions, quoted and re-checked
43. New Hampshire: Section 78-A:4-a Advertisements of Short-Term Rentals, quoted and re-checked

Written October 13, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.