Build an ADU in Wilton.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Wilton — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
8 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Wilton zoning ordinance · source · 2026-07-07
- Front
- 35 ft
- Side
- 35 ft
- Rear
- 35 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
The town's default and principal single-family district: it encompasses ALL land in Wilton not in the Residential, Commercial, Industrial or Office Park Districts (6.0.1) - the large majority of the town.
- Front
- 35 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 43,560 sf (~1.00 ac)
Higher-density village residential district (specific tax-map areas in Wilton village, Wilton Center and West Wilton). Min lot TIERED BY UTILITIES: 1 acre (43,560 sf) per dwelling unit for lots NOT served by both Town water and sewer (CONSERVATIVE tier recorded here); 1/2…
- Front
- 35 ft
- Side
- 25 ft
- Rear
- 20 ft
- Max coverage
- 75% impervious
- Min lot
- —
Setbacks: front 35 ft, side 25 ft, rear 20 ft; no buildings or parking in the front setback or in any setback abutting a residentially/residential-agriculturally zoned parcel; parking allowed to within 10 ft of side/rear line abutting another commercial or industrial parcel…
- Front
- 25 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- —
Adopted March 2019 for the downtown core (Main Street / Forest Road lots). Setbacks: front 25 ft, side 15 ft, rear 15 ft; on Main Street Overlay lots, setbacks are instead 'at a depth to conform with existing neighboring buildings'; no buildings/parking in front setback or…
- Front
- 75 ft
- Side
- 35 ft
- Rear
- 35 ft
- Max coverage
- 60% impervious
- Min lot
- 87,120 sf (~2.00 ac)
RESIDENTIAL USES PROHIBITED (8.5). Front setback measured FROM THE EDGE OF THE PUBLIC RIGHT-OF-WAY: 75 ft on all public roads generally (recorded here), 100 ft along NH Route 101; side/rear 35 ft; no buildings or parking in the front setback or any setback abutting…
- Front
- 25 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 17,424 sf (~0.40 ac)
NEW - adopted March 2026 Town Meeting (Ch 8A); overlay on specified downtown mill-area Industrial District lots allowing adaptive reuse for multi-family housing, commercial, light industry and mixed use.
- Front
- 100 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- —
- Min lot
- 217,800 sf (~5.00 ac)
Corporate office / research / farming campus district (single mapped area, lot C-172-1 and part of C-127-3); no residential use listed. Min lot 5 acres (217,800 sf) with a minimum of 2 acres excluding wetlands and water bodies (9.3.1); frontage 200 ft Class V or better (9.3.2).
- Front
- 200 ft
- Side
- 200 ft
- Rear
- 200 ft
- Max coverage
- 20% impervious
- Min lot
- 43,560 sf (~1.00 ac)
Planned-development OVERLAY district: a Research and Office Park must be at least 25 acres; no building may be constructed on any lot within a park smaller than 1 acre (43,560 sf, recorded as the per-lot floor) (9A.5.1).
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Wilton 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 Wilton (Hillsborough County). A detached ADU can be up to 950 sf.
In Wilton's GRA zone, ADUs follow the single-family setbacks: 35 ft front, 35 ft side, and 35 ft rear. Wilton has 8 zoning districts in total — see the full table below. Confirm your exact zone with the town.