This story is part of Planning's Disruptors series, a year-long look at the trends, challenges, and opportunities driving change in our communities.
By Robert Liberty
Before Los Angeles and New York adopted the first residential zoning regulations more than a century ago, rapidly growing cities in the U.S. were filled with an interesting mix of housing types beyond single-family detached homes: downstairs apartments, cottages, duplexes, tri- and four-plexes, townhomes, boarding houses, garden court apartments — what we now call "middle housing." But as cities embraced single-family detached residential (SFR) zoning, middle density housing was outlawed in many places.
By 2019, multifamily housing was barred from about 75 percent of residential land in the U.S. That's made huge swaths of American cities and their better public schools off-limits to families of modest means who can't afford single-family homes, which has in turn reinforced racial, ethnic, and class segregation. SFR zoning has also separated people from jobs, shops, and services, leading to longer commutes and more personal vehicles — one of the main sources of greenhouse gas emissions — than people in the U.S.
But now, the tide is turning. From Oregon to Vermont, cities and states are rejecting two cornerstones of American land-use regulation: SFR zoning and minimum parking requirements. A trio of reforms has emerged to take their place, aiming to create more inclusive, equitable, and affordable neighborhoods by expanding housing options.
As we head into a new decade, planners should expect to see these changes gain momentum in communities of all sizes.
1. Eliminating SFR-only Zoning
In 2018, Minneapolis made headlines by amending its comprehensive plan to allow duplexes and triplexes on single-family lots, which translated into changes in its zoning ordinance just last year. It was the first place in the U.S. to make such a fundamental change across all of its single-family zones by reauthorizing these types of "missing-middle" housing.
Oregon wasn't far behind. In 2019, the state passed a law that requires all cities with a population over 10,000 to allow duplexes on all lots in SFR zones. Tri-and fourplexes, townhomes, and cottage cluster housing were also made legal in cities with over 25,000 people. This year, Portland went a step further and allowed six-plexes on single-family lots, provided that two units meet rental or ownership affordability standards.
Most recently, Nebraska required in August that cities with over 20,000 people prepare and implement housing affordability plans over the next few years. Failure to adopt them by the deadline triggers default housing regulations, authorizing the full range of middle housing.
Even smaller cities like Lander, Wyoming, with a population around 7,500, are rethinking SFR zones.
2. Embracing ADUs
Accessory dwelling units, or ADUs (also known as granny flats, English basements, secondary suites, casitas, and ohana houses), are another way to increase housing diversity and affordability, but they've been banned from SFR zones for decades. In 2005, Vermont changed course by enacting a law that mandated the equal treatment of different housing types in local bylaws, including ADUs in SFR zones. Soon, other states followed.
California required local governments to authorize ADUs in SFR zones in 2016. The following year, New Hampshire passed legislation ensuring that, in the absence of local zoning authorization, state law directly allows one ADU as an accessory use to any single-family dwelling, as a matter of right, and no municipal permits or conditions can be imposed other than a building permit. Oregon's law, adopted the same year, mandates ADU authorization in most cities.
These early regulations weren't perfect. ADU construction still faced roadblocks due to "poison pills," like requiring owner occupancy, minimum parking standards, or approval through discretionary conditional use processes like public hearings — a process not imposed on single-family homes. California, Vermont, Oregon, and Washington have since amended their statutes to remove or severely limit poison pills, as have local governments like Seattle and Montgomery County, Maryland. In late 2019, for example, California passed five new bills that reduce barriers to ADU construction in SFR neighborhoods, including eliminating owner-occupancy requirements and certain impact fees. Local jurisdictions are even responsible for providing ADU grant and incentive programs.
The results have been impressive: In 2016, Los Angeles issued 117 permits for ADUs; in 2019, it issued 4,606.
3. Housing people over cars
Minimum on-site parking requirements create a significant barrier to multifamily housing. They not only drive up costs but can make construction either infeasible or physically impossible, given the lot size or terrain.
That's why more and more advocates and planners are questioning why housing for cars is mandated at the expense of housing for people. Parking expert Professor Donald Shoup, FAICP, of UCLA estimates that the U.S. has set aside two billion parking spaces for just 250 million cars and light trucks, resulting in far more land dedicated to cars than housing.
Sand Point, Idaho, was the first to eliminate all parking requirements in 2009. Years later, in 2016, Hartford, Connecticut, became the first major city to eliminate all minimum parking requirements, and even imposed limits on the maximum amount of on-site parking allowed. Buffalo, New York, followed suit in 2017, and Edmonton, Alberta, did the same this past summer, becoming Canada's first city to do so. Others still have reduced or eliminated parking requirements for new housing, particularly near transit stops, like in San Diego and Atlanta.
Further Impacts: Housing
Planners must also maintain focus on rising rates of homeless; gentrification and displacement; rent-burdened households; and the rise of one-person households.
More to come
More local governments and states will adopt these zoning reforms in the coming years, as the affordability crisis and concerns about social justice persist. Time will tell how quickly and in what ways they will result in a more enriched mix of housing in former SFR areas.
In our highly polarized nation, we can also expect opposition from those who see reform as part of a "war on the suburbs." Planners, on the other hand, might take these changes as long overdue recognition of the important roles they, and zoning, play in the form and character of our cities, towns, and suburbs.
Robert Liberty is a land-use attorney. He is currently associated with Cascadia Partners, an Oregon planning consulting firm, and serves as chair of the Columbia River Gorge National Scenic Area Commission.