In 2019, Seattle made it easier to build accessory dwelling units (ADUs). Among other things, they started allowing two ADUs per lot, they stopped requiring the owner to live on site, and they stopped requiring off-street parking. The result is that the city is now permitting close to 1,000 ADUs per year (2022 figure). And for the first time ever, this figure now exceeds the number of permits issued for single-family houses.
Part of what's driving this adoption is that the City created 10 pre-approved plans that owners/builders can choose from. And since they were launched in September 2020, these plans have been permitted 130 times. (Los Angeles did something very similar with its "standard plan program.")
In general though, Seattle's policies seem more permissive than what we have here in Toronto. According to this recent "annual report", it is estimated that about 12% of ADUs in Seattle are licensed as short-term rentals. About a third are also being permitted as condominiums. In Toronto, any sort of severance is heavily discouraged. The objective was and is to create new rental housing.
But for Seattle, this seems to be creating more affordable homes for sale. The median selling price for an ADU is apparently $732,000, compared to $1.2 million for a single-family house. This sounds kind of good.
Image: The Seattle Times
The city of Los Angeles has taken an interesting approach to accessory dwelling units (what we generally call laneway or garden suites here in Toronto). In an effort to streamline the approvals process and bolster the supply of housing in the city, they've gone out and pre-approved a series of "standard plans" that you can quickly implement on your property. The idea here is that all of their approved plans have already been checked for compliance with the various building codes. So those reviews don't need to happen before a permit can be issued (though the building department would still need to review any site-specific conditions).
What that means is that if you're in the market for, say, a one-storey, one-bedroom ADU at around 450 sf, you can simply scroll through their list and find the one you like the most. Here is one that fits this criteria by Design, Bitches (I just wanted to mention this firm name). The potential downside of this approach is that it could encourage less architectural experimentation. On the flipside, many of their approved designs are really nice and so maybe it's a boon for those who are lacking in good taste. Either way, if you want to encourage more of something, the way to do that is to reduce friction.
To start to give you a sense of how meaningful this could become, the city of Los Angeles received 1,980 applications for ADU construction back in 2017. This is the year in which the state changed its regulations so that ADUs were no longer prohibited in some municipalities (I don't know all of the specifics truthfully). Last year, LA saw 5,374 applications and I suspect the number will be even higher this year. Should other cities look at pre-approving certain designs? And could this be an approach used for even larger building typologies? Speed is good.