| Max size | 1,000 sq ftconditioned living area |
|---|---|
| Min size | No town minimumbuild as small as code allows |
| Bedrooms | Up to 2 |
| Type | Attached or detacheddetached: within 75 ft of the house |
| Parking | 2 spaces1 must be dedicated to the ADU |
| Owner-occupancy | Requiredin either the ADU or the primary home |
| Short-term rental | Not stated |
| Utility connection | Tie into the existing electrical connection or choose a separate metersame statewide |
The July 2025 state law (RSA 674:71–73) overrides local ordinance language that conflicts with it — even language a town still has posted. Here's what that means in Northwood:
Northwood's ordinance effectively requires two dedicated on-site spaces whenever you add an ADU, without pointing to any separate rule that already required parking for your house in the first place, and without letting you choose an off-site spot instead. Under state law as of July 2025, the town can only tack on one extra space if it already required parking for your primary home, and you get to choose on-site or off-site.
On a large lot (Northwood's baseline single-family minimum is 2 acres), a strict 75-foot leash on where a brand-new detached ADU can sit could meaningfully limit siting options. The ordinance already carves out an exemption for converting an existing garage or barn, which covers the clearest state-law-protected case, but whether the 75-ft cap on a newly-constructed detached unit is itself an impermissible extra restriction is a judgment call for an attorney.
This rule bars a new driveway cut for an ADU — not necessarily a new front door. It's plausibly a legitimate road-safety/access-management rule rather than a violation of the state's entrance-choice protections, but it restricts practical ADU placement on some lots and deserves a specific attorney read against RSA 674:72 before treating it as settled either way.
This isn't a familial-relationship requirement (which state law clearly bars), but it is a numeric occupancy cap that the familial-relationship prohibition doesn't clearly address one way or the other. Flag it for attorney review rather than calling it compliant or non-compliant.
Under the July 2025 state law (RSA 674:71-73, as amended by HB 577), one ADU — attached or detached — is yours by right wherever single-family homes are allowed, and where a town rule is stricter, state law controls. Northwood's Development Ordinance (adopted 1999, revisions through March 11, 2025) already delivers that baseline: it allows one accessory dwelling unit by right, town-wide, in its single unified 'General District' — no special exception, conditional use permit, or site plan review required, just a building permit and occupancy permit (§IV.B.(6)(d)). Both attached (shared-wall) and detached ADUs are explicitly allowed, up to 1,000 sq ft of conditioned living area (more generous than the state's 950 sq ft default cap) with no stated minimum size, up to two bedrooms, and the owner must live in either the primary home or the ADU. Where Northwood likely falls short of the July 2025 state law floor: (1) the town requires a minimum of TWO parking spaces once an ADU is added, with at least one 'dedicated' space specifically for the ADU — there's no other rule in this ordinance establishing that a house without an ADU already needs off-street parking, and no mention of the owner's state-law right to choose an off-site space instead; (2) a detached ADU must sit within 75 feet of the primary dwelling's foundation (waived only for conversions of an existing garage or barn), which could meaningfully limit siting on Northwood's typically large (2-acre-minimum) lots; (3) ADUs may only use existing curb cuts for ingress/egress, which may or may not run afoul of the state's entrance-choice protections depending on how a court reads 'ingress/egress'; (4) a cap of two unrelated occupants inside the ADU isn't clearly addressed by state law either way. None of these were revisited after March 2024, so the ADU rules predate HB 577's July 1, 2025 effective date — Northwood has not yet published any amendment reconciling these specific points, and where they conflict with the state floor, state law controls. See conflicts[] for full citations and resolved_by_town[] for what the town already had right.
Get a free personalized report for your address in Northwood — including where the 2025 law works in your favor.
Get My Free Northwood ADU Report →House Bill 577 (2025) amended RSA 674:72, effective July 1, 2025. Wherever Northwood's ordinance is stricter than this floor, the state law controls. Read the full NH ADU law explainer →
Yes — Northwood allows one accessory dwelling unit (attached or detached) by right, town-wide, with only a building permit required. Under RSA 674:72 (as amended effective July 1, 2025), one accessory dwelling unit — attached or detached — is allowed by right on single-family lots statewide.
1,000 sq ft — conditioned living area. State law doesn't let any town cap ADU size below 750 sq ft.
Attached or detached (detached: within 75 ft of the house). Since July 1, 2025, state law allows detached ADUs by right statewide — town provisions that prohibited them are superseded.
2 spaces — 1 must be dedicated to the ADU. State law caps what any town can require at one additional space, located on- or off-site at the owner's choice.
Required — in either the ADU or the primary home. Where owner-occupancy is required, state law lets the owner choose which unit to live in.