Build an ADU in Lisbon.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Lisbon — 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 Lisbon zoning ordinance · source · 2026-07-07
- Front
- 25 ft
- Side
- 10 ft
- Rear
- 25 ft
- Max coverage
- —
- Min lot
- 80,000 sf (~1.84 ac)
PRIMARY residential district for most homeowners: District D is the catch-all — 'all other property not included in Districts A, B, C or the Industrial District' (Sec 3.1.4), i.e. All uses: min lot 80,000 sf, frontage 125 ft, front setback 25 ft, side 10 ft, rear 25 ft (Sec 5.8).
- Front
- 50 ft
- Side
- 10 ft
- Rear
- 25 ft
- Max coverage
- —
- Min lot
- 80,000 sf (~1.84 ac)
Lisbon zones by geography, not by use-type: District A is the strip north of the southernmost NH railroad ROW crossing on US Route 302, between the Ammonoosuc River and a line 1,250 ft from Route 302 (Sec 3.1.1).
- Front
- 25 ft
- Side
- 10 ft
- Rear
- 25 ft
- Max coverage
- —
- Min lot
- 20,000 sf (~0.46 ac)
District B is all property south of District A, between the Ammonoosuc River and the top of the terrace bank formed by the river (Sec 3.1.2) — the denser village-terrace area. All uses: min lot 20,000 sf, frontage 125 ft, front setback 25 ft, side 10 ft, rear 25 ft (Sec 5.8).
- Front
- 25 ft
- Side
- 10 ft
- Rear
- 25 ft
- Max coverage
- —
- Min lot
- 20,000 sf (~0.46 ac)
District C is all property not in District A or B that is serviced by the Lisbon Public Water system (Sec 3.1.3) — the water-served residential/mixed area. All uses: min lot 20,000 sf, frontage 125 ft, front setback 25 ft, side 10 ft, rear 25 ft (Sec 5.8).
- Front
- 50 ft
- Side
- 25 ft
- Rear
- 25 ft
- Max coverage
- —
- Min lot
- 80,000 sf (~1.84 ac)
Industrial District: property along Mt. Eustis Road from the Littleton/Lisbon line to Streeter Pond Road, within 3,000 ft south of the Ammonoosuc high-water mark, excluding Streeter Pond Road frontage (Sec 3.1.5).
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Lisbon 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 Lisbon (Grafton County). A detached ADU can be up to 950 sf.
In Lisbon's D zone, ADUs follow the single-family setbacks: 25 ft front, 10 ft side, and 25 ft rear. Lisbon has 5 zoning districts in total — see the full table below. Confirm your exact zone with the town.