Instantly look up zoning rules, setbacks, and permit requirements for your specific town — translated from legal jargon into plain English, and verified by a real human right here in NH.
✓ Accessory Dwelling Units are allowed by right statewide
Click any town to see a plain-language breakdown of what you can build — no legal degree required.
New Hampshire's ADU law changed significantly with the passage of House Bill 577 in July 2025. Then, each town updated their specific zoning regulations in March 2026. Let us cut through the noise and give you exactly what you need to know about what's allowed in your specific town.
Enter your town. Our system pulls the most current zoning ordinance — including the 2025 state law changes that most town websites haven't clearly posted yet.
We translate complex legal language into clear, actionable information. See exactly what size ADU you can build, setback requirements, parking rules, and permit steps.
✓ Every town cross-checked line-by-line against the 2025 state law
Enter your contact info to unlock your personalized ADU breakdown — a detailed look at your town's rules and where the 2025 law works in your favor.
Stop guessing. Get a personalized report for your specific town — including its current rules, the 2025 law changes, and most importantly, a translation of what it all means.
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Yes! House Bill 577 took effect July 1, 2025, significantly expanding Accessory Dwelling Unit rights. Every single family property in NH can now build an attached OR detached ADU by-right. No special permits, meetings, or conditional use approvals required! Many town websites haven't fully updated their zoning pages to reflect this, or it's buried under lots of other zoning regulations you don't have time to sift through. That's exactly why this guide exists.
An attached ADU shares a wall with your main home, think a finished basement apartment or an addition. Sometimes the shared wall is a breezeway, mudroom, or hallway. A detached ADU is a completely separate structure on your property, like a backyard cottage or garage conversion. Both are allowed by-right in every NH town, but there are still other parts to the puzzle your property needs to comply with. This guide helps you get those pieces in place.
No, but this is where it can get complicated. While state law sets the floor, municipalities can still impose other reasonable conditions like setbacks, maximum & minimum square footage, owner-occupancy, and parking. Our town lookup shows you both the state baseline and your specific local rules side by side, including where the town's posted rules are now overridden by the 2025 law.
Great question! The answer is a big 'ol "it depends". Costs vary based on size, type, location, site prep, utility connections, and your town's requirements. An Accessory Dwelling Unit is a real house, just a little bit smaller. Therefore, it's going to add tremendous value and equity to the property as a whole. Families typically spend between $275,000 - $400,000+ depending on what they design, and there are ADU-specific financing solutions available right here in New Hampshire to help you bring this project to life.
Every guide is reconciled with the July 2025 state law (RSA 674:71–73).