Bridgewater, New Hampshire · Grafton County

Build an ADU in Bridgewater.

Allowed by-right · RSA 674:71-73

New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Bridgewater — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.

All zoning districts in Bridgewater

4 districts

Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.

Verified against the official Bridgewater zoning ordinance · source · 2026-07-07

GRPrimary

General Residential District (Lake District & River Road District)

Art. III.D.1 (lot, coverage, frontage); Art. IV.B (setbacks); Art. IV.C (height); Art. IV.I (Pemigewasset shoreline)

Front: 35 ft
Side: 20 ft
Rear: 20 ft
Max coverage: 30% impervious
Min lot: 87,120 sf (~2.00 ac)

Principal residential district, split geographically into the Lake District (west side of town along Route 3A) and River Road District (east side along the Pemigewasset River). Setbacks are TOWN-WIDE per Art IV.B: 35 ft between any structure and the EDGE of any highway,…

Mountain District (formerly Rural Residential)

Art. III.D.2 (lot, coverage, frontage); Art. IV.B (setbacks); Art. IV.C (height)

Front: 35 ft
Side: 20 ft
Rear: 20 ft
Max coverage: 15% impervious
Min lot: 217,800 sf (~5.00 ac)

Low-density rural/open-space district covering the environmentally sensitive mountain areas; the Zoning Map key notes 'Rural Residential' was renamed the Mountain District. Setbacks are the town-wide Art IV.B standards: 35 ft from edge of road/ROW (public or private), 20 ft…

Commercial District

Art. III.D.3 (uses, cross-reference to GR dimensions); Art. III.D.1.b (incorporated GR standards); Art. IV.B (setbacks); Art. IV.C (height)

Front: 35 ft
Side: 20 ft
Rear: 20 ft
Max coverage: 30% impervious
Min lot: 87,120 sf (~2.00 ac)

Commercial corridor along Route 3A (from Lot #109-15 north to Whittemore Point Road N., 500 ft deep on the west side; and on the east side of Route 3A from Lot #108-2 north 500 ft deep to Dick Brown Brook — per the Zoning Map description).

Commercial/Industrial District

Art. III.D.4 (uses, cross-reference to GR dimensions); Art. III.D.1.b (incorporated GR standards); Art. IV.B (setbacks); Art. IV.C (height); Art. IV.I (shoreline)

Front: 35 ft
Side: 20 ft
Rear: 20 ft
Max coverage: 30% impervious
Min lot: 87,120 sf (~2.00 ac)

Area bounded by the Plymouth town line, the Pemigewasset River, and a line 500 ft west of and parallel to Route 3 (Zoning Map description). Dimensions: 'Lot and frontage requirements shall be the same as those applicable in the General Residential District-Lake District &…

Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.

Note: Bridgewater is beyond ~1 hour from our Madbury home base, so a travel-time allowance may be added — we'll spell it out in your quote.

Confirm your zoning

Bridgewater zoning ordinance ↗Bridgewater parcel map (AxisGIS) ↗

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Bridgewater ADU FAQ

Can I build an ADU in Bridgewater, NH?

Yes. Under NH RSA 674:71-73 (HB 577), one accessory dwelling unit is allowed by-right on single-family lots statewide, including Bridgewater (Grafton County). A detached ADU can be up to 950 sf.

What are the ADU setbacks in Bridgewater?

In Bridgewater's GR zone, ADUs follow the single-family setbacks: 35 ft front, 20 ft side, and 20 ft rear. Bridgewater has 4 zoning districts in total — see the full table below. Confirm your exact zone with the town.

ADU rules in nearby Grafton County towns

Ashland Bath Benton Bethlehem Bristol Campton Dorchester Easton