Build an ADU in Lyme.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Lyme — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
8 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Lyme zoning ordinance · source · 2026-07-07
- Front
- 75 ft
- Side
- 35 ft
- Rear
- 35 ft
- Max coverage
- 12% lot
- Min lot
- 217,800 sf (~5.00 ac)
Principal district of the town; 'Single Dwelling' is a use permitted by right here (Table 4.1). Min lot size TIERS by location (sec 5.11 B / Table 5.1): three acres for land within 1,000 ft of the state highways and FIVE acres for all other land.
- Front
- —
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 12% lot
- Min lot
- 43,560 sf (~1.00 ac)
Village mixed-use residential core (with Lyme Common). Min lot 1 acre = 43,560 sf. Road (front) setback is NOT a fixed number: per sec 5.13 C and Table 5.1 row c ('See Section 5.13C'), in the Lyme Center and Lyme Common Districts the minimum road setback for new…
- Front
- —
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 12% lot
- Min lot
- 43,560 sf (~1.00 ac)
Village mixed-use residential core (with Lyme Center); objectives are village character with a mix of residential and neighborhood business/civic uses (sec 3.21). Min lot 1 acre = 43,560 sf. Road (front) setback = median setback of the five closest buildings on the same side…
- Front
- 150 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- 20% lot
- Min lot
- 87,120 sf (~2.00 ac)
Route 10 mixed-use commercial/light-industrial district that also permits residential (Single Dwelling is by-right, Table 4.1). Min lot 2 acres = 87,120 sf. Road/front setback measured from ROW line or, if unknown, from a line 25 ft from the road centerline (Art II SETBACK).
- Front
- 150 ft
- Side
- 150 ft
- Rear
- 150 ft
- Max coverage
- 12% lot
- Min lot
- 653,400 sf (~15.00 ac)
Remote, low-intensity district; Single Dwelling permitted by right (Table 4.1). Min lot 15 acres = 653,400 sf. Min road frontage 600 ft; min lot width 500 ft; max height 35 ft; waterfront lots need 300 ft water frontage (sec 5.22).
- Front
- 75 ft
- Side
- 35 ft
- Rear
- 35 ft
- Max coverage
- 12% lot
- Min lot
- 87,120 sf (~2.00 ac)
Small-lot district in the East Lyme area, created to allow reasonable use of pre-zoning small lots (sec 3.24.1); Single Dwelling permitted by right (Table 4.1). Min lot 2 acres = 87,120 sf. Min road frontage 150 ft; min lot width 200 ft; max height 35 ft.
- Front
- 40 ft
- Side
- 150 ft
- Rear
- 150 ft
- Max coverage
- 2% lot
- Min lot
- 2,178,000 sf (~50.00 ac)
Special district reserved for the existing ski area; Single Dwelling is NOT permitted (N in Table 4.1) - primary use is Skiing Facilities by Site Plan Review. Min lot 50 acres = 2,178,000 sf. Table 5.1: road (front) 40 ft, side 150 ft, rear 150 ft For Skiing Facilities use…
- Front
- 150 ft
- Side
- 150 ft
- Rear
- 150 ft
- Max coverage
- 2% lot
- Min lot
- 2,178,000 sf (~50.00 ac)
Very-low-intensity conservation district for remote forest tracts; Single Dwelling permitted by right (Table 4.1) but at very large lot sizes. Min lot 50 acres = 2,178,000 sf. A Double Density Option (sec 5.11 D.6) can permit twice the base number of lots if 90%+ is kept as…
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Lyme 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 Lyme (Grafton County). A detached ADU can be up to 950 sf.
In Lyme's Rural zone, ADUs follow the single-family setbacks: 75 ft front, 35 ft side, and 35 ft rear. Lyme has 8 zoning districts in total — see the full table below. Confirm your exact zone with the town.