Build an ADU in Bethlehem.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Bethlehem — 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 Bethlehem zoning ordinance · source · 2026-07-07
- Front
- 60 ft
- Side
- 30 ft
- Rear
- 30 ft
- Max coverage
- 25% building
- Min lot
- 80,000 sf (~1.84 ac)
The town's general/rural district and principal single-family residential zone: it covers all of Bethlehem outside the Village District except Districts III, IV and V, and single-family dwellings 'with or without an Accessory Dwelling Unit' are a permitted use.
- Front
- 60 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- 25% building
- Min lot
- 40,000 sf (~0.92 ac)
All area within the Bethlehem Village District except District I - Main Street. Front setback 60 ft MEASURED FROM CENTERLINE of the right-of-way (Art II.C). Frontage 150 ft Max building coverage 25%; green space >=33%.
- Front
- 60 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- 25% building
- Min lot
- 20,000 sf (~0.46 ac)
Route 302 frontage from Lewis Hill Road east to Turner Street; principal access must be onto US Route 302. Front setback 60 ft from centerline, and per Art II.C the front setback in this district applies ONLY to the side bordering Main Street.
- Front
- 60 ft
- Side
- 30 ft
- Rear
- 30 ft
- Max coverage
- 25% building
- Min lot
- 80,000 sf (~1.84 ac)
Industrial/commercial district (specific tax-map lots off Map 405/406/416). Front setback 60 ft from centerline; side/rear 30 ft, reducible up to 15 ft by ZBA Special Exception. Frontage 200 ft Max building coverage 25%; green space >=33%.
- Front
- 60 ft
- Side
- 30 ft
- Rear
- 30 ft
- Max coverage
- 25% building
- Min lot
- 80,000 sf (~1.84 ac)
Light industrial/commercial district (Map 404 Lot 6). Front setback 60 ft from centerline; side/rear 30 ft, reducible up to 15 ft by ZBA Special Exception. Frontage 200 ft Max building coverage 25%; green space >=33%.
- Front
- —
- Side
- —
- Rear
- —
- Max coverage
- —
- Min lot
- —
Landfill-only district (Map 419 Lots 22-23). Town-wide Art II standards (40 ft height, 33% green area) still apply.
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Bethlehem 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 Bethlehem (Grafton County). A detached ADU can be up to 950 sf.
In Bethlehem's II zone, ADUs follow the single-family setbacks: 60 ft front, 30 ft side, and 30 ft rear. Bethlehem has 6 zoning districts in total — see the full table below. Confirm your exact zone with the town.