Build an ADU in Stratham.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Stratham — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
9 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Stratham zoning ordinance · source · 2026-07-05
- Front
- 30 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 20% building
- Min lot
- 87,120 sf (~2.00 ac)
2 acres. Duplex needs 3 ac. Min 60% open space.
- Front
- 30 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 25% building
- Min lot
- 43,560 sf (~1.00 ac)
1 acre.
- Front
- 30 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 30% building
- Min lot
- 43,560 sf (~1.00 ac)
1 acre. Side/rear 30 when abutting residential.
- Front
- 60 ft
- Side
- 25 ft
- Rear
- 25 ft
- Max coverage
- 40% building
- Min lot
- 43,560 sf (~1.00 ac)
1 acre. No public water/sewer tier (conservative).
- Front
- 40 ft
- Side
- 10 ft
- Rear
- 20 ft
- Max coverage
- 60% building
- Min lot
- 43,560 sf (~1.00 ac)
1 acre. Open space 30%. Footprint max 80,000 sf.
- Front
- 30 ft
- Side
- 25 ft
- Rear
- 25 ft
- Max coverage
- 40% building
- Min lot
- 43,560 sf (~1.00 ac)
1 acre. Footprint 80,000 sf.
- Front
- 30 ft
- Side
- 40 ft
- Rear
- 50 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
2 acres. Coverage cell garbled — null to avoid guessing.
- Front
- 40 ft
- Side
- 40 ft
- Rear
- 40 ft
- Max coverage
- 40% building
- Min lot
- 217,800 sf (~5.00 ac)
5 acres.
- Front
- —
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 10% building
- Min lot
- 87,120 sf (~2.00 ac)
2 acres. Front contextual (avg of abutters, max 35 ft).
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Stratham 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 Stratham (Rockingham County). A detached ADU can be up to 950 sf.
In Stratham's RA zone, ADUs follow the single-family setbacks: 30 ft front, 20 ft side, and 20 ft rear. Stratham has 9 zoning districts in total — see the full table below. Confirm your exact zone with the town.