Build an ADU in Goffstown.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Goffstown — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
10 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Goffstown zoning ordinance · source · 2026-07-06
- Front
- 25 ft
- Side
- 15 ft
- Rear
- 30 ft
- Max coverage
- 25% building
- Min lot
- 43,560 sf (~1.00 ac)
Utility tiering: min lot 1.0 ac (43,560 sf) with no town utilities, 1.0 ac with either water or sewer, 0.5 ac (21,780 sf) with both; min frontage 150 ft (None/Either) or 100 ft (Both). Density on a sliding scale 3-6 du/buildable acre [note 7].
- Front
- 25 ft
- Side
- 15 ft
- Rear
- 30 ft
- Max coverage
- 25% building
- Min lot
- 40,000 sf (~0.92 ac)
Utility tiering: min lot 40,000 sf with no town utilities, 20,000 sf with either water or sewer, 10,000 sf with both; min frontage 100 ft in all tiers. Density on a sliding scale 4-8 du/buildable acre [note 8].
- Front
- 100 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- 5% building
- Min lot
- 217,800 sf (~5.00 ac)
No town utilities. Min lot 5.0 ac; min frontage 300 ft; max 0.5 du per buildable acre; max height 35 ft; max non-ag building footprint 5,000 sf.
- Front
- 35 ft
- Side
- 25 ft
- Rear
- 30 ft
- Max coverage
- 10% building
- Min lot
- 87,120 sf (~2.00 ac)
No town utilities. Min lot 2.0 ac; min frontage 200 ft; max 0.8 du per buildable acre [note 3: a two-family dwelling allowed if lot has both 3 ac and 300 ft frontage]; max height 35 ft; max non-ag building footprint 5,000 sf.
- Front
- 25 ft
- Side
- 15 ft
- Rear
- 30 ft
- Max coverage
- 25% building
- Min lot
- 43,560 sf (~1.00 ac)
Utility tiering: min lot 1.0 ac with no town utilities, 1.0 ac with either water or sewer, 0.5 ac with both; min frontage 150 ft (None/Either) or 100 ft (Both). Density 1/2/6 du per buildable acre by tier.
- Front
- 25 ft
- Side
- 15 ft
- Rear
- 30 ft
- Max coverage
- 25% building
- Min lot
- 40,000 sf (~0.92 ac)
Utility tiering: min lot 40,000 sf with no town utilities, 20,000 sf with either water or sewer, 10,000 sf with both; min frontage 100 ft in all tiers. Density 1/4/8 du per buildable acre by tier.
- Front
- 10 ft
- Side
- 10 ft
- Rear
- 25 ft
- Max coverage
- 90% building
- Min lot
- 5,000 sf (~0.11 ac)
No town-utility tiering. Min lot 5,000 sf; min frontage 50 ft; max 15 du per buildable acre; max height 45 ft; max non-ag building footprint 8,000 sf [note 5: more by Planning Board CUP].
- Front
- 10 ft
- Side
- 10 ft
- Rear
- 25 ft
- Max coverage
- 40% building
- Min lot
- 5,000 sf (~0.11 ac)
Min lot 5,000 sf; min frontage 50 ft; max 15 du per buildable acre; max height 45 ft; max non-ag building footprint 15,000 sf [note 5].
- Front
- 25 ft
- Side
- 10 ft
- Rear
- 25 ft
- Max coverage
- 40% building
- Min lot
- 43,560 sf (~1.00 ac)
Min lot 1.0 ac; min frontage 50 ft; max height 45 ft; max non-ag building footprint 25,000 sf [note 5].
- Front
- 50 ft
- Side
- 25 ft
- Rear
- 25 ft
- Max coverage
- 50% building
- Min lot
- 87,120 sf (~2.00 ac)
Min lot 2.0 ac; min frontage 50 ft; dwelling-unit density N/a; max height 45 ft; max non-ag building footprint 50,000 sf [note 5].
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Goffstown 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 Goffstown (Hillsborough County). A detached ADU can be up to 950 sf.
In Goffstown's R-1 zone, ADUs follow the single-family setbacks: 25 ft front, 15 ft side, and 30 ft rear. Goffstown has 10 zoning districts in total — see the full table below. Confirm your exact zone with the town.