In July 2025, New Hampshire Governor Kelly Ayotte signed a slew of bills easing restrictions on residential construction in order to encourage more building across the state.
House Bill 577, which is already in effect, altered NH RSA 674:71-72 to permit the expansion of Accessory dwelling Units (ADUs) in New Hampshire.
- The new law permits the construction of detached units, requires municipalities to permit at least one such detached unit per lot, and increases the maximum square footage allowed per unit. This is an improvement over the prior law, which only permitted attached units
,and gives homeowners and builders
House Bill 631, which goes into effect on July 1, 2026 under NH RSA 674:77-78, will require municipalities to allow multi-family residential development in commercial zones.
- Allows for the possibility of “mixed-use” developments containing both commercial and residential areas.
- The new law will require that there is adequate infrastructure to support the new developments, such as roads, water, and sewage systems.
- Requires municipalities to also provide exemptions for setbacks, height and frontage for such mixed-use developments.
These new bills, either already or soon-to-be State Law, will pair will with House Bill 457, which prohibits local zoning from restricting the number of residents to less than two (2) persons per bedroom in dwellings, and Senate Bill 284, which prohibits local rules requiring more than one parking space per unit for residential construction. Additional laws were also passed related to inspections, including changes to reviews by the Department of Transportation (NHDOT) and Department of Environmental Services (NHDES), which are aimed at shortening the inspection process for newly constructed housing and developments.