Bolthole Index

Hillsborough County, New Hampshire

Zoning, building permits and septic rules in Nashua, New Hampshire

Nashua, New Hampshire requires a building permit for a home, and the city, not Hillsborough County, issues it under its own Land Use Code1. Nashua writes and enforces its own zoning ordinance2. Septic systems need approval from both the New Hampshire Department of Environmental Services and the city's Environmental Health Department3.

At a glance

Building permit
Required; issued by the City of Nashua Department of Building Safety14
Zoning
Yes, Nashua's own Land Use Code (Chapter 190, Part 2)2
Septic
State (NHDES) and city Environmental Health approval both required3
Public sewer
Buildings within 100 feet of a public sewer must connect5
Minimum lot, R-40 district
40,000 square feet (about one acre)6
Minimum lot, R-30 district
30,000 square feet7
Earth pit privies
Prohibited citywide8
RV and tiny-home living
Not confirmed; ask Planning and Zoning9

Who to call

Building permits

City of Nashua Department of Building Safety

Building permit applications, plan review and inspections inside Nashua city limits

603-589-3080

[email protected]

229 Main Street 2nd floor of City Hall Nashua NH 03060

Zoning

City of Nashua Planning and Zoning (City Hall)

Site plans, change of use and zoning questions; the same page lists fees for building permits

603-589-3090

Septic permits

City of Nashua Environmental Health Department

Local septic approval: test pit observations, plan reviews and bed bottom inspections

603-589-4530

[email protected]

18 Mulberry Street, Nashua, NH 03060

Septic permits

City of Nashua Environmental Health: Sewage & Septic Systems page

Local septic approval requirements and fees

Septic permits

New Hampshire Department of Environmental Services, Subsurface Systems Bureau

State approval for septic system construction and operation, required statewide

(603) 271-3503

29 Hazen Drive, Concord, NH 03302-0095

Contact details are copied from each office’s official page and were checked against it on October 24, 2026.

Off-grid gear

Going off-grid in Nashua means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in Nashua, NH, and who issues it?

Yes. Nashua's Land Use Code says no residential development is approved unless it conforms to the code "and a building permit is issued in accordance with part 3"1. The City of Nashua Department of Building Safety handles the application at City Hall, and its permit email is [email protected]4. New Hampshire's state building code applies to all construction in the state10, and the permit follows the locally adopted process where a municipality enforces the code11.

The permit covers structure only. Separate permits are required for plumbing, electrical or mechanical work, and each permit carries an additional $35 filing fee9. Part 3 of the Land Use Code lays out the application steps12. We could not confirm which building code chapter or inspection schedule the city applies, so ask the Department of Building Safety4.

Does Nashua have zoning, and what does it mean for lot size?

Yes. Part 2 of Nashua's Land Use Code is the city's zoning ordinance, setting zoning districts, overlay districts and special districts along with use regulations and dimensional standards2. The residential districts are R-40, R-30, R-18, R-9, R-A, R-B and R-C13.

The rural residential R-40 district has a minimum lot size of 40,000 square feet, or approximately one acre6. The R-30 district is similar, with a minimum of 30,000 square feet7. Both figures come from the code's district purpose statements, so confirm them against the dimensional table before you buy. Overlay districts, such as the water supply protection and historic districts, can override base district rules2. We could not confirm setbacks, lot coverage or height limits; call Planning and Zoning9.

How do septic permits work inside Nashua?

Inside Nashua, a septic system needs two approvals: one from the New Hampshire Department of Environmental Services and one from the city's Environmental Health Department14. No building permit is issued until both are in place, where the work requires them3. State approval for construction and approval for operation are both required before the system is used15.

Construction may not start until the city approves the system, and approval is not issued where connecting to the public sewer is feasible and reasonable16. Buildings within 100 feet of a public sewer must connect to it5. The city's local fees include $50 per test pit observation14. Earth pit privies are prohibited citywide, and one septic tank may not serve more than one property8.

Can you live in an RV or tiny home in Nashua?

We could not confirm Nashua's rules for living in an RV, camper or tiny home on private land, so do not assume either is allowed. Ask Nashua Planning and Zoning before you buy or park anything9. New Hampshire's statewide campground rule covers recreational campgrounds and camping parks, not a single residential lot, and it leaves local zoning in force17. Any dwelling with plumbing also needs a septic or sewer solution approved by the city3.

Building a home in Nashua: the steps, in order

  1. Call Planning and Zoning to confirm your district and the lot rules that apply9.
  2. If the lot is not on public sewer, have the city Environmental Health Department witness test pits and review your plans18.
  3. Obtain state septic approval from the Department of Environmental Services15.
  4. Apply for the building permit with the Department of Building Safety; the permit is issued after zoning and other approvals1.
  5. Pull separate plumbing, electrical and mechanical permits9.
  6. Request inspections as work proceeds; a change in use involving a septic system also needs a certificate of compliance from Environmental Health before a certificate of occupancy19.

What stays with Hillsborough County, and what to check before you buy in Nashua?

Hillsborough County does not zone or issue building permits in Nashua: New Hampshire law leaves planning and zoning with municipal government20. Septic approval stays with the state, working alongside the city21. For land outside city limits, see the Hillsborough County page.

Before buying, check whether public sewer is within reach, since that changes your septic options5. Only 6.8% of soils in Hillsborough County rate as not limited for a conventional drain field, so expect a site evaluation and possibly an engineered system22. Hillsborough County's effective property tax rate is 1.8%23. We could not confirm well permit rules or driveway access rules in Nashua; ask the Department of Building Safety.

Watch-outs

  • We could not confirm Nashua's building code chapter, owner-builder rules, accessory dwelling rules or full permit fee schedule; call the Department of Building Safety before you plan4.
  • Minimum lot sizes come from district purpose statements, so confirm them against the code's dimensional table6.
  • The city's septic ordinance was revised in January 2025, so older advice on local septic rules may be out of date16.

Sources

  1. City of Nashua Land Use Code, Chapter 190, Article II-III base districts and dimensional regulations (eCode360) (Nashua), quoted and re-checked
  2. City of Nashua Land Use Code, Chapter 190, Article I introduction (eCode360) (Nashua), quoted and re-checked
  3. City of Nashua Code Chapter 255 Sewage Disposal, Article VII Individual Sewage Disposal Systems (eCode360) (Nashua), quoted and re-checked
  4. City of Nashua Department of Building Safety (nashuanh.gov)
  5. City of Nashua Code Chapter 255 Sewage Disposal, Article VII Individual Sewage Disposal Systems (eCode360) (Nashua), quoted and re-checked
  6. City of Nashua Land Use Code, Chapter 190, Article II-III base districts and dimensional regulations (eCode360) (Nashua), quoted and re-checked
  7. City of Nashua Land Use Code, Chapter 190, Article II-III base districts and dimensional regulations (eCode360) (Nashua), quoted and re-checked
  8. City of Nashua Code Chapter 255 Sewage Disposal, Article VII Individual Sewage Disposal Systems (eCode360) (Nashua), quoted and re-checked
  9. City of Nashua Planning and Zoning (City Hall) (nashuanh.gov)
  10. Chapter 155-A New Hampshire Building Code, quoted and re-checked
  11. RSA 155-A:4 Permit Required, quoted and re-checked
  12. City of Nashua Land Use Code, Chapter 190, Article I introduction (eCode360) (Nashua), quoted and re-checked
  13. City of Nashua Land Use Code, Chapter 190, Part 2 zoning districts and supplemental use regulations (eCode360) (Nashua), quoted and re-checked
  14. City of Nashua Environmental Health: Sewage & Septic Systems page (nashuanh.gov)
  15. New Hampshire Department of Environmental Services, Subsurface Systems Bureau (des.nh.gov)
  16. City of Nashua Code Chapter 255 Sewage Disposal, Article VII Individual Sewage Disposal Systems (eCode360) (Nashua), quoted and re-checked
  17. Chapter 216-I Recreational Campgrounds and Camping Parks (New Hampshire statewide rule), quoted and re-checked
  18. City of Nashua Environmental Health Department (nashuanh.gov)
  19. City of Nashua Code Chapter 255 Sewage Disposal, Article VII Individual Sewage Disposal Systems (eCode360) (Nashua), quoted and re-checked
  20. gc.nh.gov, quoted and re-checked
  21. Chapter 485-A Water Pollution and Waste Disposal, quoted and re-checked
  22. 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
  23. Effective property tax rate: Bolthole Index county data

Written October 24, 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.

Answers from the rulebook for Nashua

Nashua’s own rules

  • Building permitRequired

    Development and residential uses inside Nashua city limits under the Land Use Code.

    • Under the Land Use Code Part 3 procedures, a building permit is issued after zoning and other approvals. Construction may not proceed before the permit is issued.
    • Sewage approvals from the state and the city are also required before a building permit (see septic_permit claim).
    “no application for development approval in the r-40, r-30, r-18, r-9, r-a, r-b, r-c zoning districts or residential uses in other districts shall be approved unless the proposed use and/or development conforms to the requirements of this article and a building permit is issued in accordance with part 3.”
  • Certificate of occupancyLimited

    Changes in configuration or use of land or buildings inside Nashua city limits that involve a sewage disposal system.

    • A certificate of occupancy for a change in configuration or use requires a valid certificate of compliance from the Environmental Health Department confirming a satisfactory disposal system.
    • General building-code certificate of occupancy rules were not opened (Chapter 105).
    “e. no certificate of occupancy approving any change in configuration or use of land or buildings shall be issued without a valid certificate of compliance issued by the environmental health department indicating that a satisfactory disposal system has been located, constructed, altered or repaired.”
  • Local zoningPresent (with conditions)

    All land and development inside Nashua city limits; the city's own Land Use Code (Chapter 190) Part 2 is its zoning ordinance.

    • Development must conform to the Land Use Code and obtain a building permit under Part 3 (see building_permit_requirement claim).
    • Overlay districts (for example the mixed use, water supply protection and historic districts) can supersede base district rules where they apply.
    “(a) part 2 is the city's zoning ordinances. this article establishes the zoning districts, overlay zoning districts, and special zoning districts as well as use regulations, and bulk and dimensional standards.”
  • Zoning districtsPublished (with conditions)

    Base zoning districts of Nashua city, including residential, commercial, industrial and downtown districts.

    • Residential districts are R-40, R-30, R-18, R-9, R-A, R-B and R-C (§ 190-17). Commercial, industrial and downtown districts are at §§ 190-18 to 190-20, plus overlay and special districts.
    “§ 190-17 residential districts (r-40, r-30, r-18, r-9, r-a, r-b, r-c). § 190-18 commercial districts (lb, gb, hb). § 190-19 industrial districts (pi, ai, gi). § 190-20 downtown districts (d-1 and d-3).”
  • Minimum lot sizeDistrict specific (with conditions)

    R-40 rural residence district inside Nashua city (southwest quadrant and similar areas); the main rural/low-density single-family district.

    • Figure taken from the R-40 purpose statement in Table 14-1 (§ 190-14). The dimensional matrix, Table 16-3 (§ 190-16), was referenced but its values were not captured, so confirm the figure against Table 16-3.
    • Where individual wells and septic systems are used, Chapter 255 septic approvals also apply (see septic claims).

    minimum lot area, R-40 district: >= 40000 sq ft (code text says approximately one acre)

    “the rural residential district has a minimum lot size requirement of 40,000 square feet (or approximately one acre).”
    One more reviewed finding on this topic
  • Who permits septicMixed (with conditions)

    Individual sewage disposal systems for buildings inside Nashua city limits.

    • The city Environmental Health Department approves the system (Chapter 255).
    • The New Hampshire Department of Environmental Services must also issue a sewage disposal approval before a building permit is issued.
    “d. no building permit shall be issued until a sewage disposal approval has been issued by the new hampshire department of environmental services, and a sewage disposal system approval has been granted by the environmental health department, if any work contemplated requires such approval or permit.”
  • Septic permitRequired

    Construction on a lot served by an individual sewage disposal system inside Nashua city limits.

    • Construction may not start until the Environmental Health Department approves the sewage disposal system.
    • Approval is not issued where connection to the public sewer is feasible and reasonable (§ 255-48(b), amended 1-14-2025 by O-24-040).
    • Approvals are valid for not more than 365 days from the date issued (§ 255-48(e)).

    approval validity: <= 365 days

    “a. no construction shall be commenced until a sewage disposal system approval has been obtained from the environmental health department.”
  • Off-grid sanitationLimited

    Non-sewered sanitation for buildings inside Nashua city limits.

    • Earth pit privies are prohibited citywide (§ 255-46).
    • Any other sanitary method must be approved by the Environmental Health Department (§ 255-45(a)).
    • One septic tank may not serve more than one property (§ 255-45(b)).
    “b. the use of an individual sewage disposal system septic tank by more than one property dwelling or other premises is prohibited.”
  • Mandatory utility hookupSewer (with conditions)

    Buildings inside Nashua city limits that are within 100 feet of a public sewer.

    • Mandatory connection applies to buildings within 100 feet of a public sewer, per NH RSA 147:8. Buildings farther away are not covered by this rule.
    • Where a public sewer abuts an existing septic property, repair or replacement of the system is not approved unless connection is shown to be impossible or highly unreasonable (§ 255-45(f)).
    • Water connection was not verified; no Nashua city water-connection rule was found in the chapter outline.

    distance to public sewer triggering connection: <= 100 ft (per NH RSA 147:8)

    “c. all buildings within 100 feet of a public sewer must connect to the public sewer per nh rsa 147:8.”
  • Subdividing landRegulated (with conditions)

    Subdivision of land inside Nashua city limits.

    • Subdivision and site plan approval are governed by Part 3 procedures and Part 4 development standards (Article XXXII covers utility standards, including individual sewage disposal systems at § 190-223).
    • Lot design, frontage and blocks are regulated under Part 4 Article XXII (§§ 190-163 to 190-166).
    “(4) part 4 contains the development standards applicable to subdivision plans and site plans.”
  • Permit processPublished (with conditions)

    Permit and approval procedures for development inside Nashua city limits.

    • Part 3 covers zoning, subdivision and site plan approvals, variances, and building permits. Each procedure section sets its own applicability and scope of approval; the Code says not all permits allow construction to begin.
    “(3) part 3 describes how to obtain a permit and describes what happens if the land use code is violated.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Nashua or Hillsborough County directly.

  • Owner-builder exemption — Owner-builder construction of a home in Nashua city.
  • Building code adopted — Building construction code adopted for Nashua city.
  • Inspections — Building inspections for construction in Nashua city.
  • Minimum dwelling size — Minimum dwelling floor area in Nashua city, single-family residential districts.
  • Setbacks — Front, side and rear setbacks for single-family lots in R-40 and R-30 districts in Nashua city.
13 more unanswered
  • Lot coverage
  • Building height
  • Living in an RV
  • Camping on your land
  • Tiny homes
  • Manufactured homes
  • Accessory dwellings
  • Septic inspection
  • Well permit
  • Agricultural exemption
  • Driveway access
  • Short-term rentals
  • Permit fees

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Unanswered questions are usually a sign that Nashua publishes no rule on the point, not that none exists. Hillsborough County’s page lists the county offices to call.

← All of Hillsborough County: county rules, score and offices