Build an ADU in Dover.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Dover — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
17 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Dover zoning ordinance · source · 2026-07-05
- Front
- 20 ft
- Side
- 20 ft
- Rear
- 30 ft
- Max coverage
- 30% lot
- Min lot
- 20,000 sf (~0.46 ac)
Build-to 20–35 (min 20). Frontage 125.
- Front
- 40 ft
- Side
- 25 ft
- Rear
- 30 ft
- Max coverage
- 10% lot
- Min lot
- 40,000 sf (~0.92 ac)
Frontage 150.
- Front
- 15 ft
- Side
- 15 ft
- Rear
- 30 ft
- Max coverage
- 30% lot
- Min lot
- 12,000 sf (~0.28 ac)
Build-to 15–25 (min 15). Frontage 100.
- Front
- 50 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 40% lot
- Min lot
- 20,000 sf (~0.46 ac)
- Front
- —
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- 40% lot
- Min lot
- 10,000 sf (~0.23 ac)
Front = avg of neighbors within 200 ft.
- Front
- —
- Side
- 15 ft
- Rear
- 30 ft
- Max coverage
- 40% lot
- Min lot
- 10,000 sf (~0.23 ac)
Front = neighbor avg.
- Front
- 15 ft
- Side
- 10 ft
- Rear
- 15 ft
- Max coverage
- 50% lot
- Min lot
- 10,000 sf (~0.23 ac)
- Front
- 30 ft
- Side
- 12 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 20,000 sf (~0.46 ac)
No coverage row extracted.
- Front
- 30 ft
- Side
- 12 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 20,000 sf (~0.46 ac)
No coverage row extracted.
- Front
- 50 ft
- Side
- 15 ft
- Rear
- 25 ft
- Max coverage
- 50% lot
- Min lot
- 40,000 sf (~0.92 ac)
- Front
- 35 ft
- Side
- 10 ft
- Rear
- 10 ft
- Max coverage
- 50% lot
- Min lot
- 20,000 sf (~0.46 ac)
- Front
- 75 ft
- Side
- 75 ft
- Rear
- 75 ft
- Max coverage
- 33% lot
- Min lot
- 217,800 sf (~5.00 ac)
5 acres.
- Front
- 50 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- 33% lot
- Min lot
- 130,680 sf (~3.00 ac)
3 acres.
- Front
- 12 ft
- Side
- 10 ft
- Rear
- 15 ft
- Max coverage
- 50% lot
- Min lot
- 10,000 sf (~0.23 ac)
- Front
- 15 ft
- Side
- 10 ft
- Rear
- 15 ft
- Max coverage
- 50% lot
- Min lot
- 10,000 sf (~0.23 ac)
- Front
- 12 ft
- Side
- 10 ft
- Rear
- 15 ft
- Max coverage
- 50% lot
- Min lot
- 10,000 sf (~0.23 ac)
- Front
- 0 ft
- Side
- 0 ft
- Rear
- 0 ft
- Max coverage
- —
- Min lot
- —
Waterfront mixed-use; setbacks 0.
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Dover 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 Dover (Strafford County). A detached ADU can be up to 950 sf.
In Dover's R-20 zone, ADUs follow the single-family setbacks: 20 ft front, 20 ft side, and 30 ft rear. Dover has 17 zoning districts in total — see the full table below. Confirm your exact zone with the town.