As walkable urban living continues to gain popularity, cities are struggling to boost the amount of housing in their core residential districts where single-family zoning locks low density in place.
This is where the dream of the 15-minute city — where people can stroll to stores, restaurants and other everyday destinations — meets the law of supply and demand.
Although 15-minute living was baked into many neighborhoods decades ago during their original development, most core residential districts long ago exhausted their capacity to grow. With inventory frozen, housing prices are soaring.
“The status quo is completely broken in terms of affordability,” said Dan Bertolet, director of research, urban planning and housing at the Sightline Institute, a Seattle think tank focused on sustainability.
Austin is a prime example. The inventory of homes for sale citywide dwindled to a scant two-week supply earlier this year compared to the six-month supply that indicates a balanced market, said Greg Anderson, director of community affairs for Austin Habitat for Humanity.
As a result, the median price of a home — which recently topped $400,000 — is no longer affordable to an Austin family of four earning the median income of $97,600, based on the rule of thumb that a buyer can afford to pay about three times their earnings. “It’s a disaster,” Anderson said.
The problem isn’t so much a lack of new construction. The problem is that the new construction isn’t producing much of a net gain in core neighborhoods — the result of a zoning code that allows only single-family homes in those areas.
“We have a lot of redevelopment happening ... but we’re getting a lot of one-for-one replacement,” Anderson said. “You have one house that’s bought for $800,000, they tear it down, they build a new home and they sell it for $1.8 million. And that’s happening all over our [core] neighborhoods.”
Codes are overdue for an overhaul that would support more diverse and affordable housing.
Back in the day, Austin, Texas, allowed duplexes, triplexes and the like in those neighborhoods, but that changed when the city adopted a new exclusionary zoning code in 1984. Many people think the code is overdue for an overhaul that would once again support a more diverse and affordable range of housing types in core neighborhoods.
“Until [then] there’s just going to be unbelievable amounts of displacement, and sprawl and unaffordability because we’re simply unable to build the amount of housing and the types of housing we’re so desperate to build,” Anderson said.
While revamping the zoning code is a contentious political process that has dragged on since 2012, the city took an important step to address its overall housing crunch when it launched the Affordability Unlocked program in 2019.
The citywide program loosens regulations on height, density, parking, compatibility and other development limitations for developers who include a high percentage of affordable apartment, condo or townhome units. The city reported certifying applications for 2,721 units as of September 2020 — 2,337 of them deemed affordable for those earning below 60 percent (renters) or 80 percent (buyers) of median-family income.
“It’s been a tremendous success,” Anderson said. “We and most other nonprofits and even for-profit affordable housing builders in Austin are definitely taking advantage of it and working toward using it more so in the future.”
Portland, Ore., once faced the same problem with exclusionary zoning like Austin, but now allows multiple units of housing on a single lot throughout the city — even in core neighborhoods previously zoned exclusively for single-family homes. The change takes effect later this year. While it puts Portland at the forefront of zoning reform nationwide, allowing multiple units on a single residential lot is nothing more than going back to the future.
“That’s a historic pattern,” said Joe Zehnder, chief planner with the city’s Bureau of Planning and Sustainability. “That’s how this town was built in the streetcar era, but we moved away from that. Now we are trying to move back to it.”
The changes come after the state Legislature required small cities to allow duplexes on single-family lots and large cities to allow four-plexes — with Portland going a step further by allowing six-plexes if at least half of the units are affordable to low-income residents.
Portland revised commercial zoning to allow more housing in and around local business districts.
Portland also revised commercial zoning to allow more housing in and around the local business districts that anchor core neighborhoods — a move that not only relieves pressure on housing supply and affordability but also expands the customer base for area merchants. The city also began prioritizing core neighborhoods when awarding funds from its affordable housing budget.
“We’re mixing it up so you have an increasingly broad range of types of units, size of units and price points in those places that already have a lot of assets,” explained Zehnder. “A lot of those [assets] like parks and schools and walkable streets are, in part, the result of past investments by the city and private development ... so we want to get the most out of that.”
But even when cities get the most out of their core neighborhoods, affordability can be a relative term. “These are high-demand and high-amenity neighborhoods,” Zehnder said. “It’s hard to [provide] affordable housing in these communities.”
That’s why Portland hopes to give newer areas of the city — former unincorporated suburbs where housing is more affordable but the amenities found in core neighborhoods are lacking — a makeover.
“In those kinds of places, we’re trying to bring more characteristics of the [15-minute city] so that those households have access to them,” Zehnder said. “And the main way we’re going to accomplish this is through private development supported by public investment ... in things like parks and walkable streets and transit.”
It’s one thing to allow multiplexes on single-family lots, but that doesn’t guarantee they will get built or be “attainably” priced if the number of allowable units is too low, warned architect Daniel Parolek, founding principal of Opticos Design in Berkeley, Calif.
Lots are so costly in many core neighborhoods that the investment — acquiring the property and in most cases tearing down an existing single-family home — must be spread across as many units as possible in order for builders to turn a profit at lower price points. Without that flexibility, builders may decide it makes more sense to simply build a seven-figure McMansion.
“Competing with the big expensive house is a real challenge,” Parolek said. “You need to make sure you’re allowing enough units.”
The threshold varies from city to city depending on property values. “In a place like Berkeley, it may take a six-plex or an eight-plex to deliver any sort of any attainability on one of these lots. In a lower-value market, the four-plex may be able to deliver an attainable rental or sale price,” Parolek said.
Parolek, who specializes in designing and planning walkable urban environments, coined the term ‘missing middle’ to describe the multiplexes, garden apartments and cottage clusters that were woven into many core neighborhoods during their birth but are rarely built anymore because of exclusionary zoning.
“I call it hidden density,” said Parolek, author of “Missing Middle Housing: Thinking Big and Building Small to Respond to Today’s Housing Crisis.”
Form-based codes give developers more leeway to choose how many units to include within the allowable envelope.
As cities ponder how to unlock that hidden density — the backbone of 15-minute neighborhoods — Parolek advises using form-based codes that focus more on the maximum building envelope rather than conventional codes that focus more on the maximum unit count.
“If a developer can only deliver four units on a lot, they’re going to deliver the biggest and most expensive units they can deliver on that site,” Parolek explained. However, if the code gives developers more leeway to choose how many units to include within the allowable envelope, they could opt to build eight studio units rather than four one-bedroom units — a win-win for supply and affordability.
“That sounds super-logical, but [conventional] zoning is set up in a way that disincentivizes smaller units,” Parolek said.
Seattle took a step in the right direction by making it easier for homeowners to build accessory dwelling units (ADUs) — granny suites, garage apartments, backyard cottages — in more of the city’s single-family neighborhoods. Bertolet calls it the most progressive ADU policy in the country because it allows for two ADUs per single-family home. The policy also limits most new single-family homes to 2,500 square feet in order to save room for ADUs — which tend to rent for below market rate — and discourage construction of expensive McMansions that consume entire lots.
The next step for Seattle is to allow missing middle housing — multiplexes, townhouses and small apartment buildings — in all residential zones, Bertolet said.
The missing middle represents the lack of choice found between single-family homes at one end of the housing market and large multifamily buildings at the other. But it also represents the lack of choice found between housing for people with below average incomes and housing for people with above average incomes.
Boulder, Colo., is known for its progressive approach to providing affordable housing at the low end of the range, but has yet to crack the code for the middle range, where developers cannot tap into government programs to subsidize their costs.
“In a place like Boulder where land values are so high, providing missing-middle housing is a tremendous challenge,” said Jacob Lindsey, director of planning and development. “We will need to innovate in [ways] we haven’t before, simply because low-income-housing, tax-credit programs don’t exist for the missing middle. It’s the next thing on our plate.”
Boulder is guided by a housing strategy that lists diverse housing choices and 15-minute neighborhoods among its goals. “Boulder is already a very compact city as a result of its comprehensive planning efforts over many years,” Lindsey said “The creation of 15-minute neighborhoods is the next logical step in its planning legacy.”
The signs of progress include three neighborhoods where planning and zoning updates support mixed-use development at previously languishing locations. Construction is already underway at Boulder Junction, a transit-oriented development where numerous local and regional bus routes converge. Construction is expected to begin soon at Alpine-Balsam, the site of an old hospital the city purchased and demolished. Still on the drawing board is East Boulder, where the city is working with the community to create a transit-oriented redevelopment plan.
Ingrid Gould Ellen calls that approach the “low-hanging fruit” when it comes to cultivating 15-minute living.
“Mixed-use zoning is at the core of building a city or neighborhood where people can live, work and play,” said Ellen, professor of Urban Policy and Planning at New York University. “The key ... is aligning zoning along transit corridors.”
Boulder’s quest to become a 15-minute city includes investing in pedestrian and bicycle infrastructure such as a multi-use pathway — separate from the sidewalks and bike lanes that line the city’s streets — that runs from one end of town to the other. “It’s like having a whole other network that connects the city in that 15-minute community type of way,” said Erika Vandenbrande, Boulder’s director of transportation and mobility.
That’s also the goal of the Atlanta Beltline, a multi-use trail being built within a former rail corridor that encircles the city. When completed, it will connect 45 core neighborhoods and increase their access to parks and Metropolitan Atlanta Rapid Transit Authority (MARTA) rail stations.
While the beltline is spurring redevelopment in places that experienced decades of disinvestment, there is a downside to the resurgence. “Because people love the beltline and want to be close to it, it’s had this unintended consequence of becoming a vehicle for gentrification and displacement,” said Amanda Rhein, executive director of the Atlanta Land Trust. “We at the Atlanta Land Trust try to mitigate some of that ... so longtime residents can remain in place as property values increase.”
Land trusts are nonprofit organizations that acquire property for a variety of community-driven purposes — including creating lasting affordable housing in high-demand neighborhoods.
When people buy a home through a land trust, they own the home but lease the land from the trust. When they sell, they gain only a portion of the home’s appreciation, which helps the land trust ensure the home remains affordable to the next buyer and the next buyer and the next buyer.
Land trusts often obtain property from land banks. Land banks are public authorities created to hold, manage and develop tax delinquent, abandoned and dilapidated properties to ensure they are transferred into productive use.
The Atlanta Land Bank is one of the Atlanta Land Trust’s primary partners. By providing land at a discount, land banks help land trusts keep their development costs down so they can price homes affordably.
Working together, land trusts and land banks provide a structure to ensure housing stays affordable for generations.
Working together, land trusts and land banks provide a structure to ensure housing stays affordable for generations, said Paul Singh, vice president of community initiatives at NeighborWorks America, a network of affordable housing advocates based in Washington, D.C.
“This ensures that long-time residents and residents with low-incomes have opportunities to live and thrive in the neighborhood even if property values rise significantly or other forces of displacement come into play,” he said.
Right now, the Atlanta Land Trust has 20 homes in its portfolio, but its five-year goal is 300 homes — both near the beltline and in other parts of the city. “What we’re trying to do is put housing in places where people have access to opportunity. That’s the bottom line for us,” Rhein said. “Some of that is basic amenities that anybody would like to have in their neighborhood, but more broadly it’s about people having access to jobs, education, health care through transportation — either MARTA or the beltline.”