Build an ADU in Andover.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Andover — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
4 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Andover zoning ordinance · source · 2026-07-07
- Front
- 30 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Principal single-family district: 'mainly districts of farms, residences and woodlands'; single-family dwellings are a PERMITTED USE by right (Art V.B.1). Setbacks are the town-wide Article IV.F standards: front 30 ft from the street right-of-way line, side and rear 15 ft Min…
- Front
- 30 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Mainly forest, woodlands and farms. Setbacks are the town-wide Article IV.F standards: front 30 ft measured from the street RIGHT-OF-WAY line (not centerline; orientation of the structure does not determine front-yard location), side and rear 15 ft from lot line.
- Front
- 30 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 43,560 sf (~1.00 ac)
Mainly residences and woodlands. Setbacks are the town-wide Article IV.F standards: front 30 ft from the street right-of-way line, side and rear 15 ft Min lot 1 acre (43,560 sf) with 150 ft frontage for newly created lots; pre-existing lots need 50 ft frontage to change use.
- Front
- 30 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 43,560 sf (~1.00 ac)
Mixed residential/commercial village centers (Andover Village and Cilleyville/East Andover; boundaries expanded at 2020 Town Meeting). Setbacks are the town-wide Article IV.F standards: front 30 ft from the street right-of-way line, side and rear 15 ft Min lot 1 acre (43,560…
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Andover 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 Andover (Merrimack County). A detached ADU can be up to 950 sf.
In Andover's AR zone, ADUs follow the single-family setbacks: 30 ft front, 15 ft side, and 15 ft rear. Andover has 4 zoning districts in total — see the full table below. Confirm your exact zone with the town.