San Francisco’s insatiable housing need should clarify the debate over restrictions that promise to incrementally boost affordable housing while exacerbating the overall shortage, making housing that much more unaffordable for everyone.

The Board of Supervisors reportedly has reached a compromise tempering last year’s voter-approved Proposition C, which more than doubled the city’s affordable-housing requirement from 12 to 25 percent for large apartment developments (those with at least 25 units). A proposed ordinance supported by Supervisors Jane Kim and Aaron Peskin, who backed the ill-advised proposition, would have barely reduced that requirement, to 24 percent; a measure supported by Supervisors London Breed, Ahsha Safai and Katy Tang, which seems to have deservedly prevailed in negotiations, would lower it more substantially, to 18 percent.

Kim and Peskin also wanted to raise requirements for condominium developments and smaller buildings (those with 10 to 24 units). Breed, Safai and Tang argued for lowering the set-aside for condominiums and opening more affordable housing to middle-income residents.

Because greater affordable-housing requirements diminish the financial feasibility of development, significantly reducing the set-aside likely would boost residential construction by 5 to 7 percent and reduce total spending on housing, according to an analysis by City Controller Ben Rosenfeld’s office. The competing proposal would have modestly increased the number of units officially designated as affordable, by 2 to 4 percent, but it was not expected to appreciably improve the supply or cost of housing over the onerous requirements set by Proposition C.

An earlier study by the controller’s office found that any affordable-housing requirement greater than 18 percent is likely to discourage development. In that light, though the supervisors appear to have made progress, their agreement starts at the upper limit of what’s reasonable and crosses into dubious territory by allowing the figure to rise to 20 percent over the next two years.

San Francisco’s population reached a record of more than 874,000 last year, according to a state report, and its housing growth was relatively brisk for a change, adding 5,000 units. But the population has expanded at nearly twice the rate of housing since 2010. Meanwhile, as the struggle to house teachers has illustrated, the city has been even worse at building middle-income housing than it has been at producing low-income units. With less than two-thirds of the estimated housing need met for at least the past decade, the city would have to maintain the unusual pace of the past year for another five years merely to close that shortfall, to say nothing of accommodating further growth.

The supervisors’ debate reflects the broader problem facing San Francisco, the Bay Area, and California. Having stifled the housing supply and driven prices skyward through over-regulation, politicians can’t fix the mess by imposing even more burdensome rules.

Competing measures

Kim-Peskin: Would increase affordable housing 2 to 4 percent but have little effect on overall supply.

Breed-Safai-Tang: Would reduce affordable housing 5 to 8 percent but boost overall supply 5 to 7 percent.

Source: City Controller’s Office