So I read in the LA times that San Francisco is considering reducing the minimum apartment size from 290 square feet to 220 square feet. In principle, I’m all for this. Apartments should be legal, SROs should be legal, mega-cheap housing options are great for the homeless to the budget-conscious.
But it’s somewhat humorous that this kind of thinking is needed in SF.
San Francisco is a ridiculously low-rise city. In the Mission District, near BART, buildings are generally 3 stories. Head west on any of the MUNI Metro lines and the building height drops to two and in places 1.5 stories. For instance, here’s western SF, less than a block from a light rail stop.
SF had relatively laissez-faire planning and zoning into the 40′s, hence the proliferation of wood-framed buildings on zero lot lines without fire walls. Then the city hit the Pacific and rents went up, slowly at first, then rapidly as the city became a cultural mecca. The people who moved in wanted to keep the city exactly as it was when they arrived, and SF land use policy became ridiculously restrictive.
SF adopting the Houston model doesn’t seem likely in this universe. So let’s posit instead that a large swath of the city was dezoned, subject to a FAR of 4:1 generally or 6:1 on transit streets. How many people could live there? Let’s look at one chunk of land, the area South of Golden Gate Park, North of Sloat, West of Highway 1, or what is sometimes called the Sunset District.
Assume 40% of the land is developable, 60% is in streets, parks, or institutional facilities (e.g. Lincoln High School). Assume that only half the developable land actually gets developed. And assume that any additional density only occurs on the additional stories. (In practice, converting single-family dwellings to apartments would increase density within the existing building envelope, but providing additional parking or retail/commercial space would reduce it).
The Sunset District measures about 1.8 by 2.2 miles, for about 2500 gross acres. 40% developable yields 1000 acres and 50% development yields 500 additional acres of building coverage. Suppose that an average apartment is 650 square feet. Since a decent chunk of the building envelope is given to non-structural usage, let’s say 1000 square feet per unit. At an average unit occupancy of 1.4, this yields over 30,000 people. But wait, there’s more.
The blocks flanking the existing LRT on Taraval and Judah measure about 700 feet on a side. Assuming these lots are allowed 6:1 FAR, and using the previous assumptions for lot developability and unit size/occupancy, these 600 gross acres yield over 7000 additional residents. Figure that slightly more lots get developed next to the train, and the total easily hits 40,000.
These are all ridiculously conservative assumptions. 1.4 persons per 650-square foot apartment is below sunbelt levels of apartment occupancy. SF is the land of six people in a two-bedroom, scraping to pay the astronomical rent. At the US-average household size of 2.6, this neighborhood holds an additional 75,000 residents.
All of this in one neighborhood, and without straying from the basic SF vernacular architecture of low/mid-rise, wood-framed buildings. Apply this same rubric to the rest of the city, allow towers in a few places, you could easily accommodate 200,000 more people – a 25% increase over the city’s current population. At the growth rate of the dot-com era, that would hold thirty years’ of population increases. At the current growth rate, it might take fifty or sixty.
So by all means, legalize micro apartments. But don’t overlook the fact that San Francisco’s current constraints on growth are almost entirely artificial.