Build an ADU in Keene.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Keene — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
24 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Keene zoning ordinance · source · 2026-07-05
- Front
- 15 ft
- Side
- 10 ft
- Rear
- 20 ft
- Max coverage
- 35% building
- Min lot
- 10,000 sf (~0.23 ac)
City water & sewer required. Impervious 45%.
- Front
- 50 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- 10% building
- Min lot
- 87,120 sf (~2.00 ac)
2 acres. Impervious 20%.
- Front
- 15 ft
- Side
- 10 ft
- Rear
- 20 ft
- Max coverage
- 35% building
- Min lot
- 8,000 sf (~0.18 ac)
Impervious 45%.
- Front
- 15 ft
- Side
- 10 ft
- Rear
- 20 ft
- Max coverage
- 30% building
- Min lot
- 43,560 sf (~1.00 ac)
No city water 1 ac (conservative); w/water 20,000. Impervious 35%.
- Front
- 15 ft
- Side
- 10 ft
- Rear
- 15 ft
- Max coverage
- 45% building
- Min lot
- 8,000 sf (~0.18 ac)
Impervious 60%.
- Front
- 15 ft
- Side
- 10 ft
- Rear
- 15 ft
- Max coverage
- 55% building
- Min lot
- 6,000 sf (~0.14 ac)
Impervious 75%.
- Front
- 50 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- 55% building
- Min lot
- 87,120 sf (~2.00 ac)
2 acres; 3,000 sf/DU. Impervious 75%.
- Front
- 20 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 80% building
- Min lot
- 15,000 sf (~0.34 ac)
Rear 50 if abutting residential.
- Front
- —
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 40% building
- Min lot
- 20,000 sf (~0.46 ac)
Front blank in ordinance. Rear 50 if abutting residential.
- Front
- 0 ft
- Side
- 5 ft
- Rear
- 10 ft
- Max coverage
- 55% building
- Min lot
- 5,000 sf (~0.11 ac)
Form-based: front build-to 0–10.
- Front
- 5 ft
- Side
- 10 ft
- Rear
- 20 ft
- Max coverage
- 55% building
- Min lot
- 8,000 sf (~0.18 ac)
Form-based: front build-to 5–10.
- Front
- 15 ft
- Side
- 10 ft
- Rear
- 15 ft
- Max coverage
- 50% building
- Min lot
- 8,000 sf (~0.18 ac)
+5,400 sf per addl DU.
- Front
- 40 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- 80% building
- Min lot
- 87,120 sf (~2.00 ac)
2 acres. Side/rear 75 if abutting residential.
- Front
- 20 ft
- Side
- 15 ft
- Rear
- 20 ft
- Max coverage
- 80% building
- Min lot
- —
Rear 50 if abutting residential.
- Front
- 50 ft
- Side
- 30 ft
- Rear
- 50 ft
- Max coverage
- 25% building
- Min lot
- 174,240 sf (~4.00 ac)
4 acres.
- Front
- 50 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 55% building
- Min lot
- 87,120 sf (~2.00 ac)
2 acres.
- Front
- 50 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- 10% building
- Min lot
- 435,600 sf (~10.00 ac)
10 acres.
- Front
- 50 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- 10% building
- Min lot
- 217,800 sf (~5.00 ac)
5 acres.
- Front
- 0 ft
- Side
- 0 ft
- Rear
- 0 ft
- Max coverage
- —
- Min lot
- —
Form-based; side/rear 0 but 15 if abutting residential/DT-T.
- Front
- 0 ft
- Side
- 0 ft
- Rear
- 0 ft
- Max coverage
- —
- Min lot
- —
Form-based; side/rear 0 but 25 if abutting residential/DT-T.
- Front
- 0 ft
- Side
- 0 ft
- Rear
- 0 ft
- Max coverage
- —
- Min lot
- 10,000 sf (~0.23 ac)
Front build-to 0–20; side/rear 0 (20/25 if abutting res).
- Front
- 0 ft
- Side
- 0 ft
- Rear
- 0 ft
- Max coverage
- 65% building
- Min lot
- —
Front build-to 0–15. Building cov 65%.
- Front
- 15 ft
- Side
- 10 ft
- Rear
- 15 ft
- Max coverage
- 50% building
- Min lot
- 8,000 sf (~0.18 ac)
Conventional setbacks.
- Front
- 30 ft
- Side
- 0 ft
- Rear
- 0 ft
- Max coverage
- 50% building
- Min lot
- —
Front 30; side/rear 0 unless abutting.
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Keene 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 Keene (Cheshire County). A detached ADU can be up to 950 sf.
In Keene's LD zone, ADUs follow the single-family setbacks: 15 ft front, 10 ft side, and 20 ft rear. Keene has 24 zoning districts in total — see the full table below. Confirm your exact zone with the town.