Build an ADU in Groton.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Groton — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
3 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Groton zoning ordinance · source · 2026-07-07
- Front
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- Side
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- Rear
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- Max coverage
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- Min lot
- 87,120 sf (~2.00 ac)
The town's principal residential district - 'the most appropriate land in Groton for building.' Permitted uses include Single-Family Residential Dwelling and one ADU, accessory structures, home occupation/business, tiny house, seasonal camp, storage structure, long/short-term…
- Front
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- Side
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- Rear
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- Max coverage
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- Min lot
- 1,089,000 sf (~25.00 ac)
Very-low-density district with limited road access, safeguarded for large-scale forestry/agriculture and wildlife habitat. Dimensional requirements are ONLY: minimum lot size 25 acres (1,089,000 sf) and minimum frontage 200 ft on state, town, and private roads (Art 4.B.III).
- Front
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- Side
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- Rear
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- Max coverage
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- Min lot
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District for commercial wind/solar, wood processing/sawmills, other businesses, recreation, RV parks, and Conservation Cluster development (which may include single-family dwellings with one ADU per dwelling) (Art 4.C.II).
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Groton 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 Groton (Grafton County). A detached ADU can be up to 950 sf.
In Groton's A zone, ADUs follow the single-family setbacks: 0 ft front, 0 ft side, and 0 ft rear. Groton has 3 zoning districts in total — see the full table below. Confirm your exact zone with the town.