Build an ADU in Webster.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Webster — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
2 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Webster zoning ordinance · source · 2026-07-07
- Front
- 100 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- —
- Min lot
- 217,800 sf (~5.00 ac)
Covers all land in town outside the Pillsbury Lake District; residential and agricultural uses only (Art III.1.B). Front setback TIERS BY LOT SIZE, not utilities: 100 ft between a building and any road or highway for lots of 5+ acres, 50 ft for all other lots (Art IV.4.A) —…
- Front
- 20 ft
- Side
- 12 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- —
Village district comprising the Pillsbury Lake Water Precinct (Plan No 2128, ~300-acre 'Hunting Preserve' area); residential uses only (Art III.1.A). Growth management: new dwelling units in the Pillsbury Lake Community are capped at 2% per year of existing units (Art 'Growth…
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Webster 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 Webster (Merrimack County). A detached ADU can be up to 950 sf.
In Webster's R/A zone, ADUs follow the single-family setbacks: 100 ft front, 50 ft side, and 50 ft rear. Webster has 2 zoning districts in total — see the full table below. Confirm your exact zone with the town.