States and cities are loosening building code requirements in an effort to lower construction costs and boost affordable housing.

Some of these changes include allowing low-rise apartment buildings to have just one stairway, reducing how often building codes are updated and rolling back specific electrical or fire safety standards.

But critics have raised safety concerns, noting that existing rules were shaped by past tragedies and aim to prevent future harm.

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For example, having only one staircase could allow a developer to add another unit or expand the size of units, said Nicolle Aube, principal and founder of Civex, a planning and civil engineering consulting firm, and an American Planning Association board member.

“But then there’s this flip side, that by removing these codes and protections, it carries this additional risk for the developer and the occupants of the building if the worst-case scenario happens,” she said.

Many states are considering single-stairway apartment laws.

They generally take one of four approaches, said Alex Horowitz, housing policy director at The Pew Charitable Trusts: begin with a study, allow single-stairway buildings statewide, update the state building code while letting local governments opt out, or give localities authority to allow them. Pew has lobbied for and testified in favor of the changes.

Two national developments could make it easier for more states and cities to allow single-stairway buildings, Horowitz said.

The first are proposed updates by the International Code Council, the organization that develops the model codes many states use as the basis for their building rules. An update to its multifamily code, for example, would allow single-stairway buildings to add a fourth story.

Second, the bipartisan 21st Century ROAD to Housing Act moving through Congress would direct the U.S. Department of Housing and Urban Development to develop model guidelines for residential buildings with a single stairway not exceeding six stories.

According to Pew, 19 states and Washington, D.C., introduced bills between 2022 and 2025 to study or allow single-stairway apartment buildings, and seven states passed them in 2025 alone.

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This year, Idaho enacted a new law that allows local governments to permit certain apartment buildings to use one stairway — generally up to six stories without an occupiable roof, or five stories with one, along with limits on units per floor, sprinklers, stair width, and smoke and fire detection.

Colorado’s law enacted last year requires certain municipalities to modify their building codes by December 1, 2027, to allow five-story multifamily residential buildings to be served by a single exit. Texas’ 2025 law lets municipalities authorize single-stairway apartment buildings up to six stories.

Colorado state Representative Andrew Boesenecker, a Democrat who sponsored the new law, came to this issue because the state needed to find a way to make smaller multifamily projects more feasible. He said the policy can help on infill lots where a traditional two-stairway apartment building may not fit.

“Single stairway or smart stairway buildings are not only a very safe way to build multi-family housing, they also bring a product to market that’s just not being offered,” Boesenecker said.

Colorado is one 16 states without a statewide building code, making local implementation a major focus. Boesenecker said lawmakers had to look at “ways that you can make it feasible through local governments to adopt this standard into their building code.”

He said the work to get the support of those skeptical of single-staircase legislation happened a year prior to the bill’s passage, when lawmakers worked with fire chiefs, fire marshals and firefighters’ unions for about a year to get them to a “neutral position” on the bill.

In Texas, Democratic state Senator Nate Johnson said the law he sponsored will allow for architectural innovation as well as maximizing multi-family housing on odd-shaped and smaller lots.

Johnson said modernizing building codes does not come at the risk of safety.

“Who knows what policies once served well and now, after decades of technological advances and changes in land use, impede good design?” Johnson said. “We have regulations for a reason, and I’m not for throwing out what protects the public. Markets tend to easily meet the challenges of sound regulatory protections.”

Lawmakers in Illinois, New York and Rhode Island considered single-stairway bills this year, but none passed before the legislatures adjourned for the year.

But moving in the opposite direction, Connecticut lawmakers this year repealed the single-stairway law they had passed in 2024, after objections from fire safety officials.

Beyond staircases, Horowitz, of Pew, said this year saw the first legislative sessions in which states have taken a look at elevators to reduce building costs. Washington state enacted a new elevator law this year that directs the state’s Building Code Council to allow smaller apartment buildings, with at most six stories and 24 units, to use smaller and less expensive passenger elevators.

Maine removed some elevator-related requirements, including for certain smoke and draft equipment and for two-way emergency video communication systems inside elevators.

Research by the Center for Building in North America, a nonprofit research group that co-authored Pew’s single-stairway report, found that installing elevators in the United States and Canada is at least three times as expensive as in Western Europe or East Asia. U.S. and Canadian installations start around $150,000, compared with roughly $50,000 in several high-income countries, the group found.

Is it safe?

Pew researchers found that modern four- to six-story single-stairway apartment buildings can be as safe as other residential buildings when they include fire-safety features such as sprinklers, smoke detectors, code-compliant drywall, self-closing doors and protected stairways.

Horowitz said Pew researchers counted every fire death in New York City and Seattle — two cities that have long allowed single-stairway apartment buildings — over 12 years.

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In New York City, Pew identified 4,440 modern single-stairway buildings and found their fire-death rate was the same as other residential buildings — about five deaths per million occupant-years. Pew also found that the deaths it identified in modern single-stair buildings appeared to occur in the unit where the fire started, not because smoke or fire penetrated the single stairway.

“Modern apartment buildings are much, much, much safer than other housing. It is not even close,” Horowitz said. “The data is clear and policymakers are following the data in this instance.”

But Sean DeCrane, the director of fire fighter health and safety operational services for the International Association of Fire Fighters, said single-stairway proposals often fail to account for residents’ potential slowness to evacuate during a fire, and how firefighters use the same stairwell to reach trapped occupants.

The IAFF cites as one example a Manhattan apartment fire on May 4 that killed three people and injured 14. The fire that trapped residents in a smoke-filled stairwell serving as the building’s only means of escape. IAFF says the fire appeared to start on the first floor and spread upward through the stairwell.

“When we take over the stairwell, occupant egress effectively stops,” DeCrane told Stateline. “So now you’re requiring firefighters to physically remove occupants out of a burning building.”

During a fire, residents may not leave when an alarm first sounds, he said, especially in apartment buildings where false alarms or smoke alarms from a kitchen mishap are common. Some residents do not try to evacuate until they smell smoke or believe they are in danger.

“Just because they hear an alarm doesn’t necessarily signify risk to them.”

Aube, of the American Planning Association, said state lawmakers should learn from California’s approach — which in 2023 directed the state fire marshal to study single-stair buildings — before lawmakers make building codes changes.

“There is a lot of technical information that lawmakers and the public need to learn before considering removing a code,” she said.

The California Office of the State Fire Marshal released that report early this year. It said safeguards such as sprinkler and smoke detectors “do not fully substitute” for having two stairwells and notes that fire departments in the state nearly unanimously oppose single stairways. But it suggested a variety of measures that should be implemented if single-stairway buildings are allowed.

Electrical codes

In recent years, some states have changed parts of their fire and electrical codes, seeking to make a dent in the total cost of a project. Arizona last year barred counties from requiring fire sprinklers in accessory dwelling units.

Indiana this year barred state and local governments from requiring arc fault circuit interrupters, or AFCIs, in certain residential buildings and emergency responder communication systems in some larger structures. AFCIs prevent electrical fires by detecting arcing in damaged or loose wiring before it builds heat inside a wall.

The Indiana bill’s lead sponsor, Republican state Representative Doug Miller, said the state needed to “put a stake in the ground” to meet its need of roughly 50,000 homes, according to the Indiana Capital Chronicle. The Indiana Builders Association said local rules accounted for 24% of the cost for a new home.

This year, Iowa changed parts of the state electrical code, including AFCI and GFCI requirements. Ground fault circuit interrupters, or GFCIs, are designed to protect people from electric shock by shutting off power when they detect a fault in the current. Supporters said these changes can help keep electrical costs low for builders and consumers.

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Iowa Democratic state Representative Jeff Cooling, who is also an electrician, said the late-session legislation takes away some kitchen GFCI requirements, removes AFCI requirements and allows cheaper ceiling boxes in places where future homeowners may install heavy fixtures or ceiling fans. He opposed the bill.

Cooling said lawmakers often talk about code changes as a way to shave costs from new housing. But as an electrician, he said many of those requirements were adopted for a reason and usually after high-profile injuries, fires or deaths prompted necessary review and updates.

“None of these codes change just to change them,” Cooling said. “They’ve changed because people have been seriously injured or killed.”

Cooling said fellow electricians he spoke with estimated the Iowa changes would save about $850 on an average new house. “That’s a rounding error,” he said.

And for Cooling, that amount of savings is too small to justify removing protections at the sake of human lives.

“It’s not the world that we want to live in where we try to balance safety and what turns out to be low-cost savings,” he said.

Waiting on new building codes

Building codes are usually updated every three years through a public process, while states and local governments retain authority to amend and enforce them.

A new law passed in Connecticut will stretch what is normally a three-year state building code update schedule into a six-year gap, pausing updates between 2024 and 2030 cycles. The state is expected to produce a report due by January 1, 2029, that will evaluate the effects of a six-year cycle for building code revisions.

Housing industry groups say Connecticut is not alone in extending or pausing the time between adopting building code changes. Last year, California froze most residential code changes through June 2031. North Carolina moved its residential code to a six-year review cycle in 2023.

The Connecticut proposal drew opposition from code officials and the International Code Council. Building officials and code organizations have warned that slowing adoption of new codes can also delay updates meant to respond to new risks.

Aube, the urban planner, said that code changes are not a silver bullet in the affordability puzzle.

“There’s not one answer,” she said. “It’s like making a cake, right? There’s a whole bunch of different ingredients that go in.”