Granny flats, also known as backyard cottages or — in the lingo of urban planners, accessory dwelling units (ADUs) — have established a better track record. Housing activists and reformers have evidence that they’ve accomplished something meaningful with these ADUs, and years of progress in both Los Angeles and Seattle can be replicated all over the country. If the goal is “build more housing now,” ADUs might be the best place to focus over the next few years.
The biggest appeal of ADUs is that they’re a complementary form of housing that avoids some of the “neighborhood character” objections that come into play when developers propose higher-intensity projects like apartment buildings or high-rises. In fact, they often serve as solutions for the kinds of residents that tend to oppose the construction of more housing. But the advantages of ADUs are numerous: They allow older residents to age in place; they create options for multi-generational living; and they can provide a source of income for retired homeowners who don’t want to move but have extra space on their property.
Encouragingly, there is evidence that where communities have focused the most on removing barriers to building ADUs, the number of these new housing units is growing — even if it took a few years to really kick in. California passed a law in 2017 that encouraged ADU construction and by 2021, more than 20% of building permit applications in the state were for ADUs. Seattle passed legislation addressing ADUs and over the past three years, ADU production in the city has increased from 279 units in 2019 to nearly 1,000 in 2022.
Progress in some places serves as inspiration for others that are struggling with housing affordability — and that’s almost everywhere these days. I serve on the Planning Commission in Brookhaven, Georgia, where I live, and as part of a zoning rewrite in 2018 the city decided to make ADUs a part of our housing affordability strategy. Unlike LA and Seattle, though, we have yet to see them gain traction in our community, which has led us to try to understand why.
Going through that process makes you appreciate how many hurdles can exist when you’re starting from zero —developers won’t want to build ADUs unless there is community demand for them, but community demand doesn’t necessarily exist until there is an awareness that ADUs are even an option — or that they’re an attractive option relative to alternatives. With fewer in-person meetings during the past three years on top of housing supply chain problems, it also has been more difficult to coordinate on new policies.
Ultimately, all these problems have solutions. It’s just about figuring out what the pain points are and addressing them, whether it means tweaking the zoning code, streamlining the permitting process, conducting community outreach or other steps.
There is a reason I’m writing this column now instead of two years ago. I’m optimistic that 2023 will be the best year yet for ADU awareness and growth. We now have municipal success stories to lead the way. For the first time since the onset of the pandemic the housing supply chain is loosening up, freeing resources for ADUs that over the past two years were absorbed by the boom in single-family housing construction.
And in an environment with higher mortgage rates than we’re used to, the granny flat provides a way to build housing that doesn’t require a huge monthly mortgage payment. I spoke with a local developer who will build a 2-bedroom ADU for around $250,000, or a 1-bedroom for $200,000.
These small homes can functionally add more housing supply than the one or two bedrooms that they contain. A downsizing retiree might be swapping out a mostly-empty 4- or 5-bedroom house in order to live in an ADU next to an adult child, for instance, freeing up that larger house for the younger household.
Time will tell if more ambitious housing reform proposals lead to the substantive change that activists seek, but in the meantime there’s momentum behind ADUs and we can make the most of those opportunities right now.
More From Other Writers at Bloomberg Opinion:
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• That Instagram Dream Home Will Have to Wait: Leticia Miranda
• Want to Cure the Housing Crisis? Kill Zoning: Virginia Postrel
This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.
Conor Sen is a Bloomberg Opinion columnist. He is founder of Peachtree Creek Investments.
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