Build an ADU in Winchester.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Winchester — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
7 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Winchester zoning ordinance · source · 2026-07-07
- Front
- 30 ft
- Side
- 10 ft
- Rear
- 10 ft
- Max coverage
- —
- Min lot
- 43,560 sf (~1.00 ac)
Art V. PRIMARY single-family residential district: 'intended to preserve a predominantly single family residential character that promotes neighborhood integrity and quality of life.' Minimum Lot and Yard Standards: lot size = 1 acre (43,560 sqft) WITHOUT water and sewer /…
- Front
- 30 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Art IV. Outlying district not served by municipal water/sewer, plus areas along primary highways; intended for larger-lot residential dwellings complemented by rural/agricultural uses. Minimum Lot and Yard Standards: lot size = 2 acres (87,120 sqft), frontage = 200 ft, depth…
- Front
- 30 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- 43,560 sf (~1.00 ac)
Art VI. Outlying parts of town not served by municipal water & sewer, plus areas along primary highways; larger-lot residential complemented by rural/agricultural uses. Minimum Lot & Yard Standards: lot size = 1 acre (43,560 sqft), frontage = 200 ft, depth = 100 ft Setbacks:…
- Front
- 10 ft
- Side
- 10 ft
- Rear
- 10 ft
- Max coverage
- —
- Min lot
- 10,000 sf (~0.23 ac)
Art VII. Minimum Lot and Yard Standards: lot size = 10,000 sqft, frontage = 75 ft, depth = 100 ft Setbacks: front = 10 ft, side/rear = 10 ft No lot-coverage or height cap stated, but a use-standard caps any commercial building footprint at 5,000 sqft; the Planning Board may…
- Front
- 20 ft
- Side
- 10 ft
- Rear
- 10 ft
- Max coverage
- —
- Min lot
- 35,000 sf (~0.80 ac)
Art VIII. Minimum Lot and Yard Standards: lot size = 35,000 sqft WITHOUT town water & sewer / 20,000 sqft WITH town water & sewer; frontage = 150 ft; depth = 100 ft minLotSqft records the CONSERVATIVE no-utilities tier (35,000); with town water+sewer it drops to 20,000.
- Front
- 100 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- —
- Min lot
- 217,800 sf (~5.00 ac)
Art VIII-A (RSA 674:21). Minimum Lot and Yard Standards: lot size = 5 acres (217,800 sqft); frontage = 500 ft on a Class II highway OR a 100-ft-wide access into the property from the Class II highway for at least 200 ft Setbacks: FRONT = 100 ft from the edge of the public…
- Front
- 50 ft
- Side
- 25 ft
- Rear
- 25 ft
- Max coverage
- —
- Min lot
- 217,800 sf (~5.00 ac)
Art VIII-A/X. Minimum Lot and Yard Standards: lot size = 5 acres (217,800 sqft), frontage = 500 ft, depth = 200 ft Setbacks: front = 50 ft, side/rear = 25 ft (one Side/Rear standard for both). The 50 ft front is a 'build-to' line so parking can go to side/rear; the Planning…
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Winchester 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 Winchester (Cheshire County). A detached ADU can be up to 950 sf.
In Winchester's Residential zone, ADUs follow the single-family setbacks: 30 ft front, 10 ft side, and 10 ft rear. Winchester has 7 zoning districts in total — see the full table below. Confirm your exact zone with the town.