The Death of Commercial-Only Zones: How NH's HB 631 is Rewriting the Rules for Developers

On July 1, 2026, New Hampshire's commercial districts will become wide open for multifamily development. House Bill 631, signed into law in July 2025, strips municipalities of the power to keep residential projects out of commercial zones, no variances, no public hearings, no special exceptions. If the property is in a Census-designated urban area and has municipal water and sewer, developers can build apartments there as a matter of right.

This isn't a minor zoning tweak. It's a fundamental shift in how New Hampshire handles land use, and it's going to reshape everything from dying strip malls to downtown office buildings. For developers, it's an open door. For towns that spent decades protecting commercial-only zones, it's a gut punch. For housing supply, it's exactly what the New Hampshire housing market forecast has been calling for.

What HB 631 Actually Does

HB 631 requires municipalities classified as "urban" by the U.S. Census Bureau to allow multifamily and mixed-use residential development on any commercially zoned land with adequate municipal water and sewer infrastructure. That means retail corridors, office parks, and commercial plazas can now be converted into apartments or mixed-use buildings without jumping through the traditional zoning hoops.

The law defines commercial zones as areas "zoned for such commercial activities as retail and office space." If your property fits that description and you're in an urban municipality, you can build housing there. Period.

Here's what developers don't need anymore:

• Conditional use permits
• Special exceptions
• Variances
• Public hearings for residential use

The only remaining municipal approval is site plan review for the residential component, which focuses on technical compliance, stormwater management, parking layout, building design, not whether the project should exist in the first place.

What Towns Are Losing (And What They Keep)

Municipalities are losing the ability to say "no" to residential development in commercial zones. They cannot impose minimum or maximum density requirements. They cannot cap building heights below 65 feet. They cannot require non-public open space or common areas beyond what's necessary for the project's function.

The traditional guardrails that protected commercial-only districts are gone. Towns that built entire economic development strategies around keeping certain corridors exclusively commercial now have to accept that those corridors are about to become mixed-use whether they like it or not.

But municipalities aren't completely powerless. They retain three key levers:

Retail Mandates: Towns can require up to 20% of ground floor space be dedicated to retail uses, preserving some commercial character even as upper floors become apartments.

Parking Requirements: Municipalities can still mandate on-site vehicle parking, which could shape project feasibility depending on how aggressively they use this authority.

Siting and Design Standards: Towns can regulate the "siting and design" of developments, provided these regulations don't "discourage the development through unreasonable costs or delay." This language is intentionally vague and will likely produce its own round of legal battles.

Towns can also still restrict residential development in industrial and manufacturing zones where incompatible uses like air pollution or noise would create health and safety issues. But for traditional commercial corridors, the battle is over.

The Developer Opportunity: Dead Malls, Strip Plazas, and Office Buildings

If you're a developer or investor looking at multifamily investing New Hampshire, HB 631 just opened up a massive inventory of underutilized commercial properties that were previously off-limits for housing.

The most obvious targets are dying retail corridors. Strip malls with 40% vacancy, office buildings that lost tenants during the remote work shift, and regional shopping centers that can't compete with e-commerce are all now candidates for residential conversion or redevelopment.

Here's why this matters: Commercial properties in urban areas already have the infrastructure developers need. They're on municipal water and sewer. They're on major roads with existing utility hookups. Many have parking lots that can be repurposed or reconfigured. The site work that makes greenfield multifamily development expensive is already done.

The economics of conversion vary widely. A single-story strip mall might be better off demolished and replaced with a ground-up multifamily project. A structurally sound office building could potentially be converted, though the floor plates and window-to-wall ratios often make this trickier than it looks on paper.

What's not variable is the zoning risk. Before HB 631, a developer looking at a commercial property for housing had to gamble on whether the town would approve a zone change or variance. That process could take years and cost tens of thousands of dollars with no guarantee of success. Now, if the property is commercially zoned and in an urban area, the zoning question is answered before you even make an offer.

This is particularly significant for smaller investors and regional developers who don't have the capital or political connections to navigate lengthy approval battles. HB 631 levels the playing field.

Impact on Housing Supply and Commercial Property Values

New Hampshire has a housing shortage, and it's not subtle. The state's housing production has lagged demand for years, driving prices up and pushing middle-income households further from job centers. HB 631 won't solve that problem overnight, but it removes a major barrier to adding housing units where people actually want to live: near jobs, services, and transit.

By converting underused commercial land into residential use, the law effectively expands the developable land supply without requiring towns to rezone residential neighborhoods or greenfield sites. That's politically valuable because it redirects growth pressure away from single-family neighborhoods, which tend to generate the loudest opposition.

The impact on commercial property values is more complex. Properties that were languishing with high vacancy rates and declining rents could see value increases as investors recognize their residential development potential. A strip mall that was worth $2 million as a marginal retail asset might be worth $4 million as a multifamily development site.

But properties with strong commercial tenants and stable cash flow could face downward pressure if the highest and best use shifts to residential. A landlord with a profitable retail center doesn't want to see their neighboring properties redeveloped as apartments if that brings more traffic, parking competition, or tenant conflicts.

The reality is that HB 631 creates winners and losers. Properties that were already struggling will likely benefit. Properties that were thriving may face new headwinds.

Critical Practical Impact

For Investors

If you're in the acquisition phase, start looking at commercially zoned properties in Census-designated urban municipalities with a new lens. Properties that were previously "commercial only" are now multifamily opportunities. Pay attention to infrastructure: municipal water and sewer are non-negotiable under HB 631.

Run the numbers on both conversion and ground-up development. The best deal might be a property where you can keep the existing structure and add density, or it might be a teardown with significant land value. Either way, the zoning risk just dropped to near zero.

Be prepared for municipalities to push back using the tools they still have. Aggressive parking requirements or design standards that "don't discourage development" (but slow it down) will be common. Budget for this friction.

For Landlords and Property Managers

If you own or manage commercial properties in urban areas, expect your tenant mix to change. Residential development next door means more foot traffic, more parking demand, and potentially different operating hours. Property management Dover NH firms are already preparing for this shift, particularly in high-growth Seacoast markets.

If you're a commercial landlord with struggling properties, HB 631 gives you an exit strategy. A property that wasn't penciling out as retail might make sense as a residential conversion or land sale to a multifamily developer.

For Tenants (Residential)

More housing supply is good for renters. HB 631 should add units in urban areas where demand is highest, which helps moderate rent growth over time. The new units will likely be market-rate, not affordable housing, but increased supply has a ripple effect across all price points.

Don't expect immediate relief. Development timelines mean projects starting in 2026 won't deliver units until 2027 or 2028 at the earliest. But the long-term trajectory is positive for renters.

For Realtors

If you work in commercial real estate, you need to understand the residential conversion potential of every listing. Properties that were previously marketed as "commercial only" now have dual-use potential, and that changes valuation and buyer profiles.

Residential agents should watch for new multifamily projects coming online in commercial corridors. These properties will need leasing and sales support, and they're going to be in urban areas where demand is strong.

What to Watch: Implementation and Pushback

HB 631 takes effect July 1, 2026, but the real fight starts after that. Municipalities that don't want residential development in their commercial zones will test the limits of their remaining authority. Expect to see aggressive use of parking requirements, design standards, and site plan review timelines as towns try to slow projects down without technically violating the law.

The phrase "discourage the development through unreasonable costs or delay" is going to generate litigation. What counts as "unreasonable"? How much delay is too much? Those questions will be answered by courts, not legislators, and the first few test cases will set the tone for how aggressively towns can push back.

Watch for municipalities to use retail mandates strategically. Requiring 20% ground floor retail on a small property could kill project economics, effectively blocking development without explicitly prohibiting it. Developers will need to underwrite this risk carefully.

Also pay attention to which municipalities are classified as "urban" by the Census Bureau. The law only applies to these areas, and the designation could shift over time as population patterns change. Smaller towns just outside the urban threshold are safe for now, but that could change in future Census cycles.

The biggest question is whether HB 631 actually produces significant housing supply or just generates legal battles and marginal projects. New Hampshire's housing shortage is real, but zoning reform doesn't automatically translate into shovels in the ground. Financing, construction costs, and market demand still have to pencil out.

If you're a developer or investor looking at the New Hampshire housing market forecast, HB 631 is a major variable. It opens up land that was previously unavailable, but it also creates uncertainty around how aggressively municipalities will use their remaining tools. The opportunity is real, but so is the friction.

For more context on how state housing mandates are reshaping local markets, check out our coverage of the MBTA Communities zoning deadline in Massachusetts, where similar state-versus-local battles are playing out in real time.