Build an ADU in Fitzwilliam.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Fitzwilliam — 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 Fitzwilliam zoning ordinance · source · 2026-07-07
- Front
- 50 ft
- Side
- 10 ft
- Rear
- 10 ft
- Max coverage
- —
- Min lot
- 40,000 sf (~0.92 ac)
Principal single-family residential district (Sec 127-4). Table of Standard Dimensional Regulations: min lot area 40,000 sf; min frontage 100 ft; min lot depth 100 ft; min front yard 50 ft; min side/rear yards 10 ft (one combined Side/Rear standard applies to both side and…
- Front
- 75 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- 120,000 sf (~2.75 ac)
Residential district (Sec 127-4). Table values: min lot area 120,000 sf; min frontage 300 ft; min lot depth 125 ft; min front yard 75 ft; min side/rear yards 20 ft (single combined Side/Rear standard); open space NR; max building coverage NR; max height 36 ft Footnote 1…
- Front
- 10 ft
- Side
- 10 ft
- Rear
- 10 ft
- Max coverage
- —
- Min lot
- —
Commercial district (Sec 127-4). Table values: min lot area NR; min frontage NR; min lot depth NR; min front yard 10 ft; min side/rear yards 10 ft (single combined Side/Rear standard); open space NR; max building coverage NR; max height 36 ft Footnote 2: where a…
- Front
- 50 ft
- Side
- 30 ft
- Rear
- 30 ft
- Max coverage
- 35% building
- Min lot
- 40,000 sf (~0.92 ac)
Commercial district (Sec 127-4). Table values: min lot area 40,000 sf; min frontage 200 ft; min lot depth 80 ft; min front yard 50 ft; min side/rear yards 30 ft (single combined Side/Rear standard); minimum open space 35%; maximum building coverage 35%; max height 36 ft…
- Front
- 100 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- 35% building
- Min lot
- 160,000 sf (~3.67 ac)
Industrial district (Sec 127-4). Table values: min lot area 160,000 sf; min frontage 200 ft; min lot depth 50 ft; min front yard 100 ft; min side/rear yards 50 ft (single combined Side/Rear standard); minimum open space 35%; maximum building coverage 35% (building-footprint…
- Front
- 100 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- 35% building
- Min lot
- 160,000 sf (~3.67 ac)
Industrial district (Sec 127-4). Table values: min lot area 160,000 sf; min frontage 200 ft; min lot depth 50 ft; min front yard 100 ft; min side/rear yards 50 ft (single combined Side/Rear standard); minimum open space 35%; maximum building coverage 35% (building-footprint…
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Fitzwilliam 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 Fitzwilliam (Cheshire County). A detached ADU can be up to 950 sf.
In Fitzwilliam's R-1 zone, ADUs follow the single-family setbacks: 50 ft front, 10 ft side, and 10 ft rear. Fitzwilliam has 6 zoning districts in total — see the full table below. Confirm your exact zone with the town.