Build an ADU in Epsom.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Epsom — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
5 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Epsom zoning ordinance · source · 2026-07-06
- Front
- 50 ft
- Side
- 15 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
PRIMARY single-family residential district: consists of all land NOT within the R/C or RLC Zones (Art II.B.3.b). Front/side/rear = 50/15/20 ft, taken from Art III.G.1.c (Single-Family Residences: 'set back from the frontage property line not less than 50 ft ...
- Front
- 50 ft
- Side
- 15 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Mixed residential + commercial district along Routes 4 and 28 near the Epsom Traffic Circle, generally 500 ft deep from the road right-of-way (Art II.B.1). Residential setbacks are the town-wide single-family standard 50/15/20 ft (front measured from the frontage property…
- Front
- 50 ft
- Side
- 15 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Light-commercial-with-residential district along Route 4 (Suncook River east to Center Hill Road) and Route 28 south to the Pembroke line, 500 ft deep from the roadway (Art II.B.2). Setbacks are the same town-wide single-family standard 50/15/20 ft (front from the frontage…
- Front
- —
- Side
- —
- Rear
- —
- Max coverage
- —
- Min lot
- —
OVERLAY district (Art II.B.4 / Art II.F) mapped on the 'Epsom Groundwater Protection District' map (CNHRPC, dated 3/8/2021); it protects aquifers/recharge areas and supplements — does not replace — the underlying R/A, R/C or RLC zone, which supplies all dimensional/setback…
- Front
- —
- Side
- —
- Rear
- —
- Max coverage
- —
- Min lot
- —
OVERLAY district adopted under RSA 674:16 (Art IV.A). It overlays and supplements the underlying zone's regulations and applies to all lands designated as Special Flood Hazard Areas by FEMA in the Flood Insurance Study for Merrimack County, NH dated January 23, 2026 and the…
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Epsom 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 Epsom (Merrimack County). A detached ADU can be up to 950 sf.
In Epsom's R/A zone, ADUs follow the single-family setbacks: 50 ft front, 15 ft side, and 20 ft rear. Epsom has 5 zoning districts in total — see the full table below. Confirm your exact zone with the town.