Build an ADU in Hudson.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Hudson — 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 Hudson zoning ordinance · source · 2026-07-06
- Front
- 30 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 43,560 sf (~1.00 ac)
PRIMARY single-family residential district (sec 334-18A): strictly residential, single-family detached homes at low densities. Minimum lot area 43,560 sf (1 acre) without Town water or sewer; reduced to 30,000 sf with both Town water AND sewer (a lot with only one utility is…
- Front
- 30 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 60,000 sf (~1.38 ac)
sec 334-18B: single-family and/or two-family (duplex) residences plus complementary uses. Minimum lot area without Town water or sewer = 60,000 sf, BUT 43,560 sf for a single-family dwelling (per the parenthetical in the table); with both Town water AND sewer = 43,560 sf.
- Front
- 30 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 10,000 sf (~0.23 ac)
sec 334-18C: established smaller-lot residential neighborhoods reflecting traditional New England town/village patterns. Minimum lot area 10,000 sf both with and without Town water or sewer (the 'without' figure carries note 1: 'Must obtain proper state/municipal permits').
- Front
- 50 ft
- Side
- 30 ft
- Rear
- 30 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
sec 334-18D: rural areas, conservation land, open space, low-density single-family. Minimum lot area 87,120 sf (2 acres) both with and without Town water or sewer. Minimum lot frontage 200 ft (both roadway classes); minimum lot width 200 ft No lot-coverage % in the table.
- Front
- 50 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 43,560 sf (~1.00 ac)
sec 334-18E: general wholesale/retail commercial, services, offices, MULTIFAMILY dwellings and accessory uses. Minimum lot area 43,560 sf (1 acre) without Town water or sewer; 30,000 sf with both Town water AND sewer (carries note 2: multifamily developments with both Town…
- Front
- 50 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 43,560 sf (~1.00 ac)
sec 334-18F: industrial development, warehousing, limited business/commercial; strictly nonresidential in character (ADUs not applicable here). Minimum lot area 43,560 sf (1 acre) without Town water or sewer; 30,000 sf with both Town water AND sewer.
- Front
- 30 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 43,560 sf (~1.00 ac)
sec 334-18G: catch-all for areas not designated R-1/R-2/TR/B/I; permits most uses allowed in the other five districts (wide diversity of land uses). Minimum lot area 43,560 sf (1 acre) both with and without Town water or sewer.
- Front
- 30 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
sec 334-18H: areas not zoned R-1/R-2/TR/B/I located OUTSIDE the right-of-way of the Circumferential Highway; rural-density version of the G District, same permitted uses as G. Minimum lot area 87,120 sf (2 acres) both with and without Town water or sewer.
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Hudson 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 Hudson (Hillsborough County). A detached ADU can be up to 950 sf.
In Hudson's R-1 zone, ADUs follow the single-family setbacks: 30 ft front, 15 ft side, and 15 ft rear. Hudson has 8 zoning districts in total — see the full table below. Confirm your exact zone with the town.