Build an ADU in Bath.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Bath — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
5 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Bath zoning ordinance · source · 2026-07-07
- Front
- 50 ft
- Side
- 25 ft
- Rear
- 25 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Default/principal district: includes ALL land in town except the Village/Business and Commercial/Industrial districts (VIII.B.3), and single-family dwellings are permitted by right (VIII.D table). Min lot 2 acres (VI.A.4).
- Front
- 50 ft
- Side
- 25 ft
- Rear
- 25 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Mixed-use village district comprising three mapped areas: Bath Village, Swiftwater Village, and the Getchell District (VIII.B.1). Min lot 2 acres (VI.A.1). Same town-wide yards (VI.A.6): front 50 ft from center line of traveled way, side 25 ft, rear 25 ft, frontage 150 ft;…
- Front
- 50 ft
- Side
- 25 ft
- Rear
- 25 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Corridor districts along US Rte 302 and Rte 112 for commercial and light-industrial uses up to 50 employees (VIII.B.2). Min lot 2 acres (VI.A.2). Same town-wide yards (VI.A.6): front 50 ft from center line of traveled way, side 25 ft, rear 25 ft, frontage 150 ft No coverage…
- Front
- 50 ft
- Side
- 25 ft
- Rear
- 25 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Historic settlement district (column 4 of the VIII.D land-usage table; boundaries in VIII.E.1). Min lot 2 acres (VI.A.3). Same town-wide yards (VI.A.6): front 50 ft from center line of traveled way, side 25 ft, rear 25 ft, frontage 150 ft No coverage limit.
- Front
- 50 ft
- Side
- 25 ft
- Rear
- 25 ft
- Max coverage
- —
- Min lot
- 261,360 sf (~6.00 ac)
Conservation OVERLAY covering all areas mapped as steep slopes (dominant slope >15%) on the town Slopes Map (VIII.F.4); where it overlaps a base district the more restrictive provision governs (Sec X).
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Bath 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 Bath (Grafton County). A detached ADU can be up to 950 sf.
In Bath's R/A zone, ADUs follow the single-family setbacks: 50 ft front, 25 ft side, and 25 ft rear. Bath has 5 zoning districts in total — see the full table below. Confirm your exact zone with the town.