Build an ADU in Warner.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Warner — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
9 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Warner zoning ordinance · source · 2026-07-07
- Front
- 50 ft
- Side
- 40 ft
- Rear
- 40 ft
- Max coverage
- —
- Min lot
- 130,680 sf (~3.00 ac)
Principal rural single-family district (chosen as primaryZone: it is the low-density residential/agricultural district covering land remote from municipal water and sewer — the bulk of Warner's residential land; R-1/R-2 are the small village and village-adjacent districts).
- Front
- 30 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 40,000 sf (~0.92 ac)
Village district where central water/sewer are available or feasible; one-family detached dwelling and accessory apartment permitted by right (Table 1). Setbacks: no building nearer than 15 ft to an abutter's property line (side = rear = 15) and 30 ft from the EDGE of a…
- Front
- 40 ft
- Side
- 25 ft
- Rear
- 25 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Planned-growth district adjacent to the village center; one-family dwelling and accessory apartment permitted by right (Table 1). Standards below apply to lots created by MINOR subdivision (Art VI.C.1, amended March 2005); lots created by MAJOR subdivision instead follow Art…
- Front
- 50 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- —
- Min lot
- 217,800 sf (~5.00 ac)
Agricultural/forestry district with 'very limited residential uses' on steep, poorly drained or flood-prone land; Table 1 nonetheless lists one-family detached dwelling and accessory apartment as permitted.
- Front
- 50 ft
- Side
- 100 ft
- Rear
- 100 ft
- Max coverage
- —
- Min lot
- 217,800 sf (~5.00 ac)
Mountain/open-land preservation district (Mt. Setbacks: 100 ft to an abutter's property line (side = rear — the largest in town) and 50 ft from the EDGE of a public right-of-way (front). Minimum Buildable Area 5 acres (217,800 sf net) with 500 ft frontage; lake/pond lots need…
- Front
- 30 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 10,000 sf (~0.23 ac)
Village business district with architectural review to preserve the 'village atmosphere'; one-family dwelling and accessory apartment permitted by right (Table 1). Setbacks: 15 ft to an abutter's property line (side = rear) and 30 ft from the EDGE of a public right-of-way…
- Front
- 40 ft
- Side
- 25 ft
- Rear
- 25 ft
- Max coverage
- 70% impervious
- Min lot
- 40,000 sf (~0.92 ac)
Highway-interchange commercial district (I-89 exits). Values shown are for lots developed for COMMERCIAL purposes (Art XI.C.1): 25 ft to an abutter's property line (side = rear), 40 ft from the EDGE of a public right-of-way (front), minimum Buildable Area 40,000 sf with 200…
- Front
- —
- Side
- —
- Rear
- —
- Max coverage
- —
- Min lot
- —
OVERLAY on part of the C-1 district near I-89 Exit 9 (approved March 2005).
- Front
- —
- Side
- —
- Rear
- —
- Max coverage
- —
- Min lot
- —
OVERLAY adopted March 2023, mapped from NHDES aquifer-transmissivity and wellhead-protection data (Art II.C.4). Regulates prohibited uses and performance standards for groundwater protection; contains no setback, lot-size or coverage standards of its own — underlying 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.
Warner 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 Warner (Merrimack County). A detached ADU can be up to 950 sf.
In Warner's R-3 zone, ADUs follow the single-family setbacks: 50 ft front, 40 ft side, and 40 ft rear. Warner has 9 zoning districts in total — see the full table below. Confirm your exact zone with the town.