Build an ADU in Barrington.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Barrington — 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 Barrington zoning ordinance · source · 2026-07-05
- Front
- 40 ft
- Side
- 30 ft
- Rear
- 30 ft
- Max coverage
- 40% impervious
- Min lot
- 130,000 sf (~2.98 ac)
130,000 sf incl 60,000 free of poor soils + 35,000 contiguous uplands.
- Front
- 40 ft
- Side
- 30 ft
- Rear
- 30 ft
- Max coverage
- 40% impervious
- Min lot
- 130,000 sf (~2.98 ac)
Identical to GR.
- Front
- 40 ft
- Side
- 30 ft
- Rear
- 30 ft
- Max coverage
- 40% impervious
- Min lot
- 80,000 sf (~1.84 ac)
Frontage 200.
- Front
- 20 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- 60% impervious
- Min lot
- 30,000 sf (~0.69 ac)
Height 40 ft / 3 stories. Frontage 75.
- Front
- 20 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- 80% impervious
- Min lot
- 20,000 sf (~0.46 ac)
Front 20 std but 50 along Rt 125/9 (conservative 50). Impervious 80%.
- Front
- 75 ft
- Side
- 30 ft
- Rear
- 30 ft
- Max coverage
- 50% impervious
- Min lot
- 40,000 sf (~0.92 ac)
Front 75 on State Highways (conservative) / 40 otherwise.
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Barrington 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 Barrington (Strafford County). A detached ADU can be up to 950 sf.
In Barrington's GR zone, ADUs follow the single-family setbacks: 40 ft front, 30 ft side, and 30 ft rear. Barrington has 6 zoning districts in total — see the full table below. Confirm your exact zone with the town.