Build an ADU in Concord.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Concord — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
18 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Concord zoning ordinance · source · 2026-07-05
- Front
- 25 ft
- Side
- 15 ft
- Rear
- 25 ft
- Max coverage
- 40% lot
- Min lot
- 12,500 sf (~0.29 ac)
Buildable 6,250. Frontage 100.
- Front
- 50 ft
- Side
- 10 ft
- Rear
- 50 ft
- Max coverage
- 40% lot
- Min lot
- 87,120 sf (~2.00 ac)
2 acres; buildable min 20,000.
- Front
- 25 ft
- Side
- 15 ft
- Rear
- 25 ft
- Max coverage
- 20% lot
- Min lot
- 40,000 sf (~0.92 ac)
No-sewer tier (conservative). W/sewer 12,500 / 40%.
- Front
- 15 ft
- Side
- 10 ft
- Rear
- 25 ft
- Max coverage
- 50% lot
- Min lot
- 10,000 sf (~0.23 ac)
- Front
- 10 ft
- Side
- 10 ft
- Rear
- 20 ft
- Max coverage
- 60% lot
- Min lot
- 7,500 sf (~0.17 ac)
- Front
- 15 ft
- Side
- 10 ft
- Rear
- 25 ft
- Max coverage
- 60% lot
- Min lot
- 10,000 sf (~0.23 ac)
- Front
- 20 ft
- Side
- 10 ft
- Rear
- 30 ft
- Max coverage
- 80% lot
- Min lot
- 10,000 sf (~0.23 ac)
- Front
- 30 ft
- Side
- 25 ft
- Rear
- 30 ft
- Max coverage
- 80% lot
- Min lot
- 25,000 sf (~0.57 ac)
- Front
- 15 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- 80% lot
- Min lot
- 12,500 sf (~0.29 ac)
- Front
- 50 ft
- Side
- 25 ft
- Rear
- 30 ft
- Max coverage
- 80% lot
- Min lot
- 40,000 sf (~0.92 ac)
- Front
- —
- Side
- —
- Rear
- —
- Max coverage
- —
- Min lot
- —
Performance district; dims not specified. Frontage 22, height 80.
- Front
- 25 ft
- Side
- 25 ft
- Rear
- 25 ft
- Max coverage
- —
- Min lot
- —
Lot/cov not specified.
- Front
- 15 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- —
Min FAR 0.3 instead.
- Front
- 25 ft
- Side
- 25 ft
- Rear
- 25 ft
- Max coverage
- —
- Min lot
- —
- Front
- 15 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- —
- Front
- 30 ft
- Side
- 25 ft
- Rear
- 30 ft
- Max coverage
- 75% lot
- Min lot
- 25,000 sf (~0.57 ac)
- Front
- 50 ft
- Side
- 25 ft
- Rear
- 30 ft
- Max coverage
- 85% lot
- Min lot
- 40,000 sf (~0.92 ac)
- Front
- 15 ft
- Side
- 10 ft
- Rear
- 25 ft
- Max coverage
- 75% lot
- Min lot
- 10,000 sf (~0.23 ac)
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Concord 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 Concord (Merrimack County). A detached ADU can be up to 950 sf.
In Concord's RS zone, ADUs follow the single-family setbacks: 25 ft front, 15 ft side, and 25 ft rear. Concord has 18 zoning districts in total — see the full table below. Confirm your exact zone with the town.