Austin, Texas, and Salt Lake City have both passed zoning reforms that will allow multiunit (or "middle housing") developments in once-single-family-only districts. Both cities are attempting to give builders more flexibility to add more housing in existing neighborhoods.
But the devil is always in the details. The particulars of Austin's reforms make it more likely that city will see more housing actually get built.
This past Thursday, the Austin City Council passed Phase One of its Home Options for Middle-income Employment (HOME) Initiative that allows three-unit homes to be built on all residential lots citywide. Previously, homeowners had only been allowed to build a single-family home and an accessory dwelling unit (ADU) (a.k.a. granny flats or in-law suites) in the city's lowest-density zones.
Other cities' triplex legalizations have produced few units because the new multiunit developments had to be roughly the same size as the single-family homes they were replacing.
Austin's reforms tweaked and simplified the city's code so that newly legal two- and three-unit homes can take up more land on each lot and be built with smaller setbacks from the street. If builders maintain the existing single-family home on the property, they'll get "preservation" and "sustainability" bonuses which allow them to cover even more of the property.
Chris Gannon, an Austin architect at Shams Gannon, says the HOME Initiative legalizes smaller, more affordable homes that Austinites want to buy.
Market data shows that when a new large home and ADU were built on the same property, "that ADU would sell immediately, while that primary [home] would sit on the market for weeks. The smaller, more affordable homes are in high, high demand."
Salt Lake City
Last Tuesday, the Salt Lake City Council passed reforms legalizing four-unit homes in all residential zones and allowing larger apartment buildings in existing multifamily areas.
On paper, that allows more housing than Austin's triplex legalization. But Salt Lake City's reforms come with some punishingly high affordability requirements in single-family zones. Builders of four-unit projects must offer half their new units (or a quarter of them if they preserve the existing home) at below-market rates.
Zoning wonks argue those affordability requirements are a huge tax on development.
Turner Bitton, of the group SLC Neighbors for More Neighbors, says that the affordability requirements will keep new fourplexes out of many single-family neighborhoods. But the multifamily reforms, which allow builders to add more floors and spread the costs of affordability mandates across more units, should be more productive, he tells Reason.