Hillsborough County, New Hampshire has no countywide building department: covered construction must comply with the state building and fire codes and needs a permit, generally through the city or town's process12. Each city and town sets its own zoning, and the county does not3. Septic permits for every address in the county, city or town alike, go through the New Hampshire Department of Environmental Services, with local approval also required where local rules say so45.
At a glance
- Building permit
- Required for covered work; follow the city or town process rather than a county process26
- Zoning authority
- Set town by town, not by the county; Manchester's Zoning Ordinance is one example73
- Septic permits
- NHDES administers approvals and inspections statewide; local officials may also have authority4
- Owner-builder (septic)
- A homeowner may build their own domicile's septic system if they certify 2 years of occupancy and hire a permitted designer or installer to certify it8
- RV on your land
- Long-term private-land occupancy is not confirmed countywide; ask the parcel's municipality7
- Off-grid toilets
- A composting or incinerator toilet needs no DES approval if the structure has no internal plumbing or water service9
- Public sewer hookup
- Required instead of a septic system if a public sewer runs within 100 feet of the building10
Who to call
Building permits
City of Manchester Planning and Community Development — Building Division
Building code administration, permit approval, field inspections, Zoning Ordinance enforcement, and certificates of occupancy for the City of Manchester — the largest city in Hillsborough County, cited here as a labeled example; every other city or town in the county has its own office
One City Hall Plaza, West Wing, Manchester, NH 03101
Septic permits
New Hampshire Department of Environmental Services — Subsurface Systems Bureau
Reviews septic system design plans and issues the Approval for Septic System Construction and Approval for Operation required statewide, including for every town in Hillsborough County
29 Hazen Drive, Concord, NH 03302-0095
Also useful
Hillsborough County Board of Commissioners
Countywide governing board; oversees corrections, the nursing home, human resources and county property, not building, zoning or land-use permitting, which sit entirely with each city or town
329 Mast Road, Suite 120, Goffstown, NH 03045
Also useful
Hillsborough County Cities & Towns Directory
Lists every city and town Hillsborough County serves, the starting point for finding your parcel's own building and zoning office
Contact details are copied from each office’s official page and were checked against it on October 10, 2026.
Off-grid gear
Going off-grid in Hillsborough County means bringing your own water and power. The kit we’d start with:
- Water Crystal Quest Filter any source — well, rain, or creek — to drinking-clean.
- Power Bluetti Solar generators and home battery backup for living off the grid.
- Septic Soil percolation test kit Run your own perc test before paying an engineer — the first thing a septic office asks about.
- Water Well water test kit Bacteria, nitrates, hardness — know what the well on a parcel is really pumping.
These are affiliate links — we may earn a commission, at no cost to you. As an Amazon Associate, Bolthole Index earns from qualifying purchases.
Do you need a building permit in Hillsborough County, New Hampshire?
Yes, for work covered by New Hampshire's building law. Buildings and structures constructed in Hillsborough County must comply with the state building and fire codes, and the person responsible for covered construction, alteration, renovation, repair, removal or demolition must obtain a permit before work begins12. Hillsborough County does not run a countywide permit counter; permitting generally follows the locally adopted process where a city or town has an enforcement mechanism62. The separate state permit system excludes one- and two-family dwellings in municipalities without a local enforcement mechanism, so ask the parcel's city or town how the permit requirement applies to your project11.
Who issues building permits in Hillsborough County, and how do you reach them?
There is no single Hillsborough County permit office; start with the city or town where the parcel lies because building permits follow the locally adopted process where the municipality has an enforcement mechanism62. Manchester's Building Division handles building-code administration, permit approval, field inspections, zoning enforcement and certificates of occupancy; reach it at (603) 624-6450 or pcd@manchesternh.gov, at One City Hall Plaza, West Wing12. For another municipality, use Hillsborough County's Cities & Towns Directory to find the correct local government13. A building official must act on a completed ordinary application within 30 days; the deadline is 60 days for nonresidential applications or residential applications covering more than 10 dwelling units14. Municipal building officials perform inspections as needed where the municipality has adopted an enforcement mechanism15.
Does Hillsborough County have zoning?
Zoning in Hillsborough County is administered by each city and town, not the county: New Hampshire law makes planning and zoning a municipal responsibility, and Manchester enforces its own Zoning Ordinance73. Local ordinances may regulate building height and size, lot size, lot coverage, yards, density and the location and use of buildings and land3. County zoning authority is limited to a county that contains unincorporated towns or unorganized places, and we could not confirm a Hillsborough County ordinance with countywide effect; ask the parcel's city or town which rules apply16. Local rules may answer lot size, setbacks, RVs, tiny homes and accessory dwellings, and those answers can change at a municipal boundary7. If you plan to subdivide, a municipal planning board may regulate subdivision only after the municipality authorizes that jurisdiction by ordinance or resolution17.
How do septic permits work in Hillsborough County?
The New Hampshire Department of Environmental Services administers septic approvals and inspections in Hillsborough County, while local health officers and other certified local officials may also have authority4. NHDES reviews design plans and, after required approvals, issues an Approval for Septic System Construction; an Approval for Operation is also required before use18. The constructed system cannot be covered or placed in operation until the department or an authorized agent completes final inspection and approval19. Construction approval is also required before converting a structure from seasonal to full-time occupancy or increasing the load on an existing system18. A homeowner building a new system for their own domicile may do the construction work personally, but must comply with NHDES rules, hire a permitted septic system designer or installer to certify that the system was built to the approved design, and certify by affidavit that the property will be the owner's domicile for at least 2 years from the date NHDES approves operation8. Confirm the paperwork directly with the Subsurface Systems Bureau18.
Can you live in an RV or tiny home on your land in Hillsborough County?
We could not confirm one countywide rule for long-term RV or tiny-home occupancy in Hillsborough County, so ask the parcel's city or town about zoning, dwelling standards and temporary use before buying7. New Hampshire's campground rules allow only temporary occupancy at recreational campgrounds, and a year-round campground site must meet the standard for a single-family house20. The reviewed campground rule does not by itself settle permanent RV living on an individual private parcel. For off-grid sanitation, a composting or incinerator toilet needs no NHDES approval only when the structure has neither internal plumbing nor supplied water service; a structure with both internal plumbing and water service needs an approved septic system even if the toilet is not connected to it9.
Building a home in Hillsborough County: the steps, in order
- Identify the parcel's city or town through Hillsborough County's directory, then ask that municipality about zoning and its permit process137.
- Submit the required building application before covered work starts; the permit must comply with the state building code and the locally adopted process where the municipality has an enforcement mechanism121.
- Allow up to 30 days for a decision on an ordinary completed application, or 60 days for a nonresidential application or a residential application covering more than 10 dwelling units14.
- Obtain required NHDES septic plan approval before constructing a building that will discharge sewage or constructing the disposal system22.
- Keep the septic system uncovered and unused until final inspection and approval19.
- Arrange municipal building inspections where the city or town has an enforcement mechanism, and ask whether it requires a certificate of occupancy before moving in1523.
What to check before you buy land in Hillsborough County
Check the parcel's city or town first, because the municipality's enforcement mechanism and zoning affect the permit path and allowed use67. Only about 7% of Hillsborough County soils rate free of severe limitations for a conventional drain field, so obtain a site evaluation before assuming a standard system will work24. Check for public sewer: a covered building generally must connect when a public sewer is within 100 feet, although municipalities may increase that distance or grant a qualifying waiver10. A seasonal camp converted to full-time occupancy needs new septic construction approval18. Also ask the municipality about driveway access, floodplain development, private-well requirements and any certificate of occupancy because we could not confirm one countywide answer for those parcel-level issues2325.
Watch-outs
- Covered construction must meet New Hampshire's building and fire codes and obtain a permit, but the administering office and process depend on the municipality12.
- Do not cover or use a new septic system until NHDES or its authorized agent completes final inspection and approval19.
- A municipality may require a certificate of occupancy before a new or remodeled building is used, so confirm the local rule before move-in23.
Sources
- Chapter 155-A New Hampshire Building Code, quoted and re-checked
- RSA 155-A:4 Permit Required, quoted and re-checked
- gc.nh.gov, quoted and re-checked
- Chapter 485-A Water Pollution and Waste Disposal, quoted and re-checked
- RSA 485-A:32 Prior Approval; Permits, quoted and re-checked
- City of Manchester Building Department FAQs (2026 county census)
- City of Manchester Zoning Ordinance (2026 county census)
- RSA 485-A:36 System Installer Permit, quoted and re-checked
- Env-Wq 1000 Subdivisions and Individual Sewage Disposal Systems (New Hampshire statewide rule), quoted and re-checked
- RSA 147:8 Toilets; Drains (New Hampshire statewide rule), quoted and re-checked
- Chapter 155-A New Hampshire Building Code (New Hampshire statewide rule), quoted and re-checked
- City of Manchester Planning and Community Development — Building Division (manchesternh.gov)
- Hillsborough County Cities & Towns Directory (hcnh.org)
- RSA 155-A:4 Permit Required (New Hampshire statewide rule), quoted and re-checked
- Chapter 155-A New Hampshire Building Code, quoted and re-checked
- RSA 674:16 Grant of Power (New Hampshire statewide rule), quoted and re-checked
- RSA 674:35 — Power to Regulate Subdivisions (New Hampshire statewide rule), quoted and re-checked
- New Hampshire Department of Environmental Services — Subsurface Systems Bureau (des.nh.gov)
- Chapter 485-A Water Pollution and Waste Disposal, quoted and re-checked
- Chapter 216-I Recreational Campgrounds and Camping Parks (New Hampshire statewide rule), quoted and re-checked
- RSA 155-A:4 Permit Required, quoted and re-checked
- RSA 485-A:32 Prior Approval; Permits (New Hampshire statewide rule), quoted and re-checked
- Chapter 155-A New Hampshire Building Code, quoted and re-checked
- Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data
- RSA 482-B:10 Record of Wells; Monitoring Wells (New Hampshire statewide rule), quoted and re-checked
Written October 10, 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.