■ TOWN-VERIFIED RULES ■
ADU Rules in New Hampshire
New Hampshire state law entitles single-family homeowners to an accessory dwelling unit, effective July 2025. Many town ordinances still contain outdated language that state law now overrides — our database reconciles both, town by town, with every rule cited to its source.
LAW: RSA 674:71-73, amended by HB 577 (2025) · PRIMARY SOURCE
// OUR DATA HERE
53 NH towns researched against current ordinances and the 2025 state-law amendments — every rule cited to its source, with human verification rolling out town by town (verified towns carry the green Human Verified tag). Parcel lookups run on NH GRANIT public records.
// FAQ
New Hampshire ADU Questions
Are ADUs legal in New Hampshire?
Yes. NH RSA 674:71-73, as amended by HB 577 in 2025, entitles owners of single-family homes to an accessory dwelling unit. Towns keep limited discretion over dimensions and process, which is why town-level rules still matter.
Does my NH town's zoning override state ADU law?
Where a town ordinance conflicts with state law, state law generally wins — but towns retain some dimensional discretion, and many posted ordinances still contain overridden language. Our screener flags exactly these conflicts for your town.
Do I need a special permit for an ADU in NH?
It depends on the town. Some towns allow ADUs by right; others use special exceptions or conditional use permits. Enter your address to see your town's current permit path.