Build an ADU in Alstead.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Alstead — 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 Alstead zoning ordinance · source · 2026-07-07
- Front
- 75 ft
- Side
- 30 ft
- Rear
- 30 ft
- Max coverage
- —
- Min lot
- 217,800 sf (~5.00 ac)
Primary/principal district: 'all land that is not specifically mentioned in the Village and Lake Districts' (District Information section). FRONT setback of 75 ft is measured from the CENTER of the travelled way, not the property line or ROW edge (Art III.E.3.a); district…
- Front
- 75 ft
- Side
- 30 ft
- Rear
- 30 ft
- Max coverage
- —
- Min lot
- 217,800 sf (~5.00 ac)
Lake Warren protection district. Min lot 5 acres (=217,800 sf), conservative/no-reduction tier; Planning Board may reduce to as low as 2 acres at its sole discretion for suitable soils/slope/access (Art III.E.1.a).
- Front
- 50 ft
- Side
- 30 ft
- Rear
- 30 ft
- Max coverage
- —
- Min lot
- 43,560 sf (~1.00 ac)
The densest village district (Alstead Village). Min lot area 1 acre (=43,560 sf) with NO discretionary reduction provision (Art III.E.1.b applies only to Village A and states 'not less than one (1) acre').
- Front
- 75 ft
- Side
- 30 ft
- Rear
- 30 ft
- Max coverage
- —
- Min lot
- 217,800 sf (~5.00 ac)
East Alstead village center. Min lot 5 acres (=217,800 sf), conservative/no-reduction tier; Planning Board may reduce to as low as 2 acres at its sole discretion for suitable soils/slope/access (Art III.E.1.a).
- Front
- 75 ft
- Side
- 30 ft
- Rear
- 30 ft
- Max coverage
- —
- Min lot
- 217,800 sf (~5.00 ac)
Alstead Center village. Min lot 5 acres (=217,800 sf), conservative/no-reduction tier; Planning Board may reduce to as low as 2 acres at its sole discretion for suitable soils/slope/access (Art III.E.1.a).
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Alstead 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 Alstead (Cheshire County). A detached ADU can be up to 950 sf.
In Alstead's Rural-Residential zone, ADUs follow the single-family setbacks: 75 ft front, 30 ft side, and 30 ft rear. Alstead has 5 zoning districts in total — see the full table below. Confirm your exact zone with the town.