Build an ADU in Effingham.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Effingham — 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 Effingham zoning ordinance · source · 2026-07-06
- Front
- 50 ft
- Side
- 30 ft
- Rear
- 50 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Primary single-family / residential district covering most of the town; purpose is to retain rural character (Sec 401). Min lot = 2 acres = 87,120 sf with 200 ft minimum frontage (Sec 402). No lot on public water may be created with less than 150 ft of shoreland frontage (RSA…
- Front
- 35 ft
- Side
- 25 ft
- Rear
- 50 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Village Overlay Districts, referred to as Village Districts; purpose is to buffer the Historic Districts and maintain historic character (Sec 401). Although labeled an 'overlay' in Sec 401, the Sec 402 dimensional table gives it its OWN distinct setbacks: front 35 / side 25 /…
- Front
- 35 ft
- Side
- 25 ft
- Rear
- 50 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Historic Districts (Center Effingham and Lord's Hill, mapped in Appendix A); purpose is to safeguard Effingham's heritage by preserving cultural resources (Sec 401, Art 15). Min lot = 2 acres = 87,120 sf, 200 ft frontage.
- Front
- 30 ft
- Side
- 20 ft
- Rear
- 30 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Province Lake District (Adopted 2007) covering lakeshore property within 300 ft of the Natural Mean High Water Elevation of Province Lake; purpose is to reflect the historical lakeshore development pattern and protect water quality (Sec 401).
- Front
- 20 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- —
Open Space Conservation Subdivision (Adopted 2015) — a conservation-subdivision design option, not a mapped base district. It is the only column in the Sec 402 table exempt from the town-wide 2-acre minimum; minimum lot size is listed as N/A (governed by 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.
Effingham 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 Effingham (Carroll County). A detached ADU can be up to 950 sf.
In Effingham's R/A zone, ADUs follow the single-family setbacks: 50 ft front, 30 ft side, and 50 ft rear. Effingham has 5 zoning districts in total — see the full table below. Confirm your exact zone with the town.