Build an ADU in Holderness.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Holderness — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
6 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Holderness zoning ordinance · source · 2026-07-07
- Front
- 35 ft
- Side
- 35 ft
- Rear
- 35 ft
- Max coverage
- 35% impervious
- Min lot
- 43,560 sf (~1.00 ac)
Principal medium-density residential district; single-family/duplex dwellings, manufactured housing, multifamily (up to 8 units/structure) and ADUs are permitted uses (300.4.1.1). Setbacks are TOWN-WIDE (Sec 400.8): 35 ft from the EDGE OF THE ROAD RIGHT-OF-WAY (not…
- Front
- 35 ft
- Side
- 35 ft
- Rear
- 35 ft
- Max coverage
- 15% impervious
- Min lot
- 43,560 sf (~1.00 ac)
Low-density rural/agricultural district covering environmentally sensitive areas; single-family/duplex dwellings, manufactured housing and ADUs are permitted uses (300.4.2.1). Same town-wide setbacks as all districts (Sec 400.8): 35 ft front from edge of road ROW, 35 ft…
- Front
- 35 ft
- Side
- 35 ft
- Rear
- 35 ft
- Max coverage
- 50% impervious
- Min lot
- 43,560 sf (~1.00 ac)
Mixed commercial district (two areas: A. Same town-wide setbacks (Sec 400.8): 35 ft front from edge of road ROW, 35 ft side/rear; front and side yards may be REDUCED for commercial buildings only, by BOA special exception after Planning Board/Health Officer review (400.8.3).
- Front
- 35 ft
- Side
- 35 ft
- Rear
- 35 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
OVERLAY extending 500 ft from the Pemigewasset River's ordinary high-water (reference) line (300.4.4.1); where superimposed over another district the MORE RESTRICTIVE regulation applies (300.4.4.2). Dwellings are NOT a listed permitted use or special exception in this overlay…
- Front
- 35 ft
- Side
- 35 ft
- Rear
- 35 ft
- Max coverage
- —
- Min lot
- —
OVERLAY covering all lands west of Interstate 93 (300.4.5.1); where superimposed over another district the more restrictive regulations apply (300.4.5.2). Use-based overlay with NO dimensional standards of its own: permitted uses are limited to those not requiring structures,…
- Front
- 35 ft
- Side
- 35 ft
- Rear
- 35 ft
- Max coverage
- —
- Min lot
- —
OVERLAY applying to Zones A/AE on the FEMA Flood Insurance Rate Maps for Grafton County dated 2024-02-08, incorporated by reference (300.4.6.1); NFIP construction/elevation standards apply and the more restrictive provision controls (300.4.6.2).
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Holderness ADU FAQ
Yes. Under NH RSA 674:71-73 (HB 577), one accessory dwelling unit is allowed by-right on single-family lots statewide, including Holderness (Grafton County). A detached ADU can be up to 950 sf.
In Holderness's GR zone, ADUs follow the single-family setbacks: 35 ft front, 35 ft side, and 35 ft rear. Holderness has 6 zoning districts in total — see the full table below. Confirm your exact zone with the town.