California steps up reform to join the single-stair bandwagon

California lawmakers have been at the forefront of zoning reforms to increase housing supply and affordability.

New legislation filed Tuesday would put the state on the path to joining single-stair reform that other states and cities have already adopted.

Assemblymember Alex Lee’s newly filed bill proposes increasing housing construction by reforming California’s building code to allow mid-rise apartment buildings with a single staircase.

Under Assembly Bill 2252, the Department of Housing and Community Development must propose building standards for multifamily residential buildings up to six stories with one stairway.

Doubling the height to six stories has been a common approach nationally. Washington, D.C., council members are one step away from final approval to relax building codes for six-story midrise buildings. Colorado, Texas, Montana and New Hampshire are among the states that have made the switch.

The Assembly Committee on Housing and Community Development will hear AB 2252 on April 22.

Another step in affordability

California lawmakers have enacted sweeping zoning reforms over the past several years to boost housing construction and ease persistent affordability pressures statewide. Dozens of state pre-emption bills have overridden local barriers to legalize accessory dwelling units, missing-middle housing, and denser infill development near transit.

Lee’s proposal targets a longstanding rule that requires two exit stairways in apartment buildings taller than three stories. Supporters say the requirement prevents developers from building efficient mid-rise housing on small urban lots, even as modern fire-prevention technology has improved safety.

“Stairway requirements can have a profound effect on what does and does not get built in our neighborhoods,” Lee said in a statement. “By unlocking previously undevelopable properties, AB 2252 will bring much-needed multifamily housing to our urban neighborhoods.”

Advocates say single-staircase buildings could reduce construction costs by 6% to 13%, according to a Pew Research Center analysis. They say changes could open the door to more compact housing and flexible unit layouts.

Building momentum

Momentum for single-stair reform has grown nationwide. Seven states passed similar legislation in 2025.

Culver City recently became the first California municipality to legalize six-story single-stair apartments. Other California cities, including San Jose and San Francisco, are studying potential reforms.

In New York City and Seattle, Pew Research showed that fire fatality rates in modern single-stair buildings are similar to those in dual-stair structures. Pew researchers also concluded that adding a second stairway wouldn’t have prevented the fire deaths recorded over 12 years in those cities.

Dallas council members chose to go taller. The city’s new code, adopted last year, allows single stairways up to eight stories.

Supporters say eliminating the second stair could make many small and irregularly shaped lots easier to develop, particularly near job centers where housing demand is highest.

Critics, including some building safety officials, say cities should proceed with caution until statewide standards are set. They argue that evacuation time and accessibility must remain priorities as housing density increases.