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