Build an ADU in New Durham.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in New Durham — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
2 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official New Durham zoning ordinance · source · 2026-07-07
- Front
- 20 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 60,000 sf (~1.38 ac)
Covers all land in town outside the Town Center Mixed Use District (Art VIII.A); single-family and two-family dwellings permitted (VIII.B.1-2). Town-wide setbacks per Art V.D: no new building less than 20 ft from the ROAD FRONTAGE PROPERTY LINE (the lot line on the road/ROW —…
- Front
- 25 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 60,000 sf (~1.38 ac)
Compact mixed-use district within 1,200 ft of the centerline of Main St/Old Bay Rd/Tash Rd/Rte 11 (south side)/Depot Rd (IX.B); Tax Maps 249-252, 257. Table 5: front yard 25 ft measured FROM THE ROAD RIGHT-OF-WAY; side and rear 15 ft for any building or structure; no…
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
New Durham 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 New Durham (Strafford County). A detached ADU can be up to 950 sf.
In New Durham's RRA zone, ADUs follow the single-family setbacks: 20 ft front, 15 ft side, and 15 ft rear. New Durham has 2 zoning districts in total — see the full table below. Confirm your exact zone with the town.