A San Francisco supervisor is trying to fix the city’s broken process for approving in-law units, which housing advocates say could create thousands of new units if the city can cut the cost and complexity of building them.

San Francisco in-law units are usually renovations of a garage, storage space, basement or attic.

“Supervisor Katy Tang’s legislation would require the three city departments in charge of approving in-law applications to have a pre-application meeting,” the San Francisco Examiner reported. “The legislation also allows new in-law units in buildings with three or fewer units.”

In June, the Examiner reported that only 23 new in-law units have been built on existing properties in the two years since the city passed new legislation to promote the units. The new units are automatically rent-controlled making them attractives to city officials, but perhaps less attractive to homeowners who may not get a return on their investment.

The cost of building these units has risen along with a general spike in construction costs, and the city’s permitting process is slow and confusing, city officials said.

It took a decade for the city’s first in-law legislation to pass, but urban planning advocacy group SPUR was hopeful in 2016 that in-laws could help address the housing crisis.

“They’re cheaper to build out than a brand-new unit, and they’re a good way to provide lower rents without government subsidy,” SPUR said in a report at the time.

SPUR cautioned when the original legislation was passed that a more flexible version of the bill might be needed to actually incentivize building these units.