Bedford NH ADU Guide: What You Can Build in 2026

ADU law update: what's changed since July

Three things have happened since we first published this guide, and all three make it easier to add a second home on a Bedford lot. First, Bedford voters approved every zoning amendment on the March 10, 2026 ballot, including Amendment No. 2. That one rewrote the town's accessory apartment rules to match state law. It removed the conditional use permit for detached ADUs and dropped any criteria that don't also apply to a single-family home. Second, HB 1079 (Chapter 210) took effect at the end of August. It defines "attached" and "detached" units and confirms that you can convert older structures, including ones that don't meet today's setbacks. Third, a separate state law that took effect September 13 lets a tiny home or yurt of 600 square feet or less count as an ADU, as long as it meets the building code.

What state law guarantees on every Bedford single-family lot

New Hampshire's HB 577 took effect July 1, 2025. It requires towns to allow at least one accessory dwelling unit, attached or detached, by right anywhere single-family homes are allowed. Towns can't add lot-size, frontage, setback or design hurdles beyond what applies to the house itself. They can't cap an ADU below 750 square feet. They can't require an interior door between the units, and they can't require the tenant to be related to you. Towns may still require the owner to live in one of the two units and may limit a lot to one ADU.

The provision most Bedford homeowners miss is the protection for existing structures. If a detached garage, barn or carriage house stood on your lot on or before July 1, 2025, the town must allow you to convert it, even if it sits inside today's setbacks or exceeds lot coverage. HB 1079 now says this in plain terms. For older Bedford properties with a barn near the lot line, that's an option new construction can't match.

Bedford's local rules after the March 2026 vote

• Detached ADUs: no Planning Board conditional use permit. Requirements that applied only to ADUs, such as the old 1.5-acre minimum for detached units, no longer apply under the amended ordinance. You still need a building permit.
• Size: Bedford's rules have long allowed up to 1,000 sq ft, or 50% of the main home for a detached unit, whichever is less. State law sets a 750 sq ft floor. Ask Planning to confirm the exact limit for your lot under the amended ordinance.
• Smaller setbacks in General Residential: Amendment No. 4 cut General Residential (GR) setbacks from 35 to 25 feet in front, and from 25 to 15 feet on the sides and rear. GR is the neighborhood northeast of Route 114 and around Sebbins Pond. On those smaller lots, a detached unit is much easier to fit.
• Septic: if you're on septic, NHDES has to approve capacity for both units. On many Bedford lots, this decides whether the project works.
• Rentals: the town's ADU fact sheet bars rentals of fewer than 30 consecutive days, so plan on long-term tenants, not Airbnb. The ADU can't be sold off separately as a condo.

The 2026 numbers

Converting existing space, such as a garage, walkout basement or bonus room over the garage, typically runs $80K–$150K. A new detached unit runs $150K–$300K+, depending on size, site work and septic. Bedford rents are some of the strongest in southern NH. One-bedroom rents have averaged about $2,350–$2,400 a month this year. A $200K detached ADU renting at $2,300 brings in about $27,600 a year before expenses, roughly a 13.8% gross yield. That doesn't count the resale value of a legal second dwelling, or what it saves to have an aging parent or adult child living close by.

Quick answers

Q: Do I still need a conditional use permit for a detached ADU in Bedford NH?
A: No. The zoning amendment Bedford voters passed on March 10, 2026 removed the conditional use permit requirement for detached accessory apartments. You still need a building permit and, if you're on septic, NHDES approval.

Q: Can I convert my old garage or barn even though it's close to the property line?
A: Yes, if it existed on or before July 1, 2025. HB 577 and HB 1079 protect those conversions even where the structure doesn't meet current setback or lot-coverage rules.

Q: Can a tiny home be my Bedford ADU?
A: Under the state law that took effect September 13, 2026, a tiny home or yurt of 600 sq ft or less can count as an ADU if it meets the state building code. Local land-use rules still apply.

Is your lot ADU-ready?

Every lot is different. Septic capacity, the driveway and what's already standing on the property all change the answer. Download our ADU Feasibility Checklist, or send us your address and The Phinney Team will do a free feasibility review of your property. We'll tell you what you could build, what it would rent for and how it would affect your home's value. For the bigger picture on Bedford NH real estate, start with our town page. If you own in a neighboring town, see our Manchester NH ADU guide and Merrimack NH ADU guide. Questions? Reach us through teamphinney.com.

This guide is general information, not legal advice. ADU rules are still changing as towns update their ordinances, so confirm current requirements with the Bedford Planning Department at (603) 472-5243 before you design or build.

Sources

• Town of Bedford 2026 Municipal Warrant (Zoning Amendments 2 and 4)
• Patch: Bedford NH 2026 Town Election Results
• Town of Bedford ADU Fact Sheet
• NH Municipal Association: The Revised Law on Accessory Dwelling Units
• NH General Court: HB 1079 (2026) bill status
• NHPR: New law enabling tiny-home construction (Aug 2026)
• Trulia: Bedford, NH rentals and rent trends