The Washington PostDemocracy Dies in Darkness

To build more ‘missing middle’ housing, the devil is in the details

Policies that roll back single-family zoning in principle get the most attention. But the fine print may have more of an impact.

Signs opposing a zoning deregulation proposal known as “missing middle” that would make it easier to build duplexes, townhouses and other structures are seen in the Lyon Village neighborhood of Arlington, Va., in January. (Craig Hudson for The Washington Post)
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The yellow house in Arlington’s Westover area that Alice Hogan bought in 2004 is a short walk from a Metro station in one direction and an elementary school in the other. It has served as the ideal place to raise her kids in this Northern Virginia suburb, she said, with diverse neighbors and easy access to plenty of small businesses.

Hogan, 53, wants more people to be able to live in the neighborhood — and under a plan before her local lawmakers this weekend to roll back residential zoning restrictions, she might get her wish.

Some of the lots on her block in this expensive county outside D.C. could be turned into a roomy set of duplexes with off-street parking. Or garden-style apartment buildings with six smaller, less-expensive units. Or they could be replaced by larger, single-family houses, just like the imposing modernist structure going up across the street from her three-bedroom Cape Cod.

What exactly, though? That might come down to the fine print.

As housing prices soar, a wealthy county rethinks the idea of suburbia

“The big line is that the devil is in the details,” said Hogan, who works in affordable housing policy. There are plenty of approaches that would allow county lawmakers to “still say they ‘ended’ single-family home-only zoning. But depending on how things shake out, they can make a tiny difference or they can make more of a difference.”

For the better part of the past year, Arlington’s “missing middle” plan has generated a polarizing debate, leading to marathon public meetings and sometimes vicious exchanges on social media. Like in other communities considering similar moves — from Victoria, B.C., to Raleigh, N.C. — residents have sparred over whether similar efforts are an effective way to combat soaring housing costs. (The median home price in Arlington was $636,500 in January, with the median single-family home going for $1.18 million.)

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  • "Missing middle” housing is a term that refers to small multiunit residential buildings like townhouses, duplexes and garden apartments.
  • It covers a range of housing types that fit into the “middle” between detached single-family houses and high-rise apartment buildings — in terms of scale, form and number of units.
  • Local laws have made it difficult or impossible to build this type of housing in many neighborhoods. That’s why advocates say it’s “missing."
  • Indeed, many suburban neighborhoods in the United States were developed under zoning rules that allow for only one house with a yard on each lot.
  • This is sometimes known as “single-family zoning.”
  • A growing list of governments, including Minneapolis and Oregon, have in recent years voted to roll back their zoning rules and make it easier to build “missing middle” housing.
  • Several localities in the D.C. area are following suit, with Arlington County leading the pack.
  • Changes like Arlington’s missing middle plan would still allow for the construction of single-family houses, which take up most of the county’s residential neighborhoods.
  • But in Northern Virginia and other communities around the country, this idea has generated a heated debate — one that has sometimes dominated local elections.
  • Many longtime homeowners say more homes and more density could ruin their single-family neighborhoods.
  • They worry that “missing middle” will crowd schools, clog sewers, remove trees and make it harder to find parking.
  • Skeptics also say the idea will not create housing for residents being priced out — and will only benefit developers instead.
  • Advocates who support missing middle say this concept will fix racist zoning policies and create more affordable housing options.
  • New duplexes or townhouses will still be expensive, they say, but will still cost less than single-family houses.
  • That will add supply to the real-estate market and bring down skyrocketing housing costs.


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Those in support of the plan, like Hogan, say it would overturn the exclusionary roots of single-family zoning and provide several smaller units on lots that could previously accommodate only one house. Over time, they say, these units would make a noticeable dent in the real estate market.

But ahead of a final series of meetings starting Saturday, critics have raised concerns about how denser housing could clog sanitary sewers, crowd schools and remove trees. Rather than diversifying their neighborhoods, they claim, it would not create more homeownership opportunities and add only the kinds of units that already exist in Arlington’s high-rise apartments.

It is because of these worries that Brian Harner, an architect and a former county planning commissioner, has urged county lawmakers to take “a careful, judicious approach,” particularly on more technical aspects of the proposal. Much of the conversation to date has framed “missing middle” as a yes-or-no debate.

“The details are important, and that’s why we need to choose the ones that preserve our ability to get the program right in the future,” said Harner, who owns a three-bedroom house in the Rock Spring neighborhood. “If we’re making choices, let’s make the right choices and understand the trade-offs.”

In a small but growing number of cities that have made headlines for “ending” single-family zoning, the technicalities of the plans appear to have played an outsize role in shaping the pace at which new, smaller-scale multifamily buildings are constructed.

Minneapolis, for instance, made national headlines when it allowed the construction of two- and three-unit buildings in any residential neighborhood. But that policy change did not appear to prompt much new housing. From the start of that policy in January 2020 through last year, just 100 new units received permits in newly legal duplexes and triplexes, according to data from city officials. The overwhelming majority of permits for new units — more than 96 percent — were issued for apartments in larger buildings.

On the other hand, lawmakers in Portland, Ore., allowed buildings with up to four units across nearly the entire city. They simultaneously changed zoning rules so that duplexes could be larger than single-family houses and three- and four-unit buildings could be larger than duplexes.

New or expanded “missing middle” housing delivered 289 units — just under three-quarters of the total built in those neighborhoods in the first year with those changes in place, according to Portland data. Planners recently revised these development standards to align with more permissive state laws, potentially ramping up housing production even further.

“We coupled allowing more units with ratcheting down the sizes of houses drastically,” said Sandra Wood, a Portland city planner who grew up in Arlington. There was not as much incentive to build the kinds of massive single-family houses that have increasingly replaced smaller homes, and builders opted for “missing middle” types instead.

Yonah Freemark, a land-use researcher at the Urban Institute in D.C., cautioned that zoning changes are just one piece of the puzzle.

There are other factors — including demand for certain kinds of units in the real estate market — that can also sway what kinds of housing might pop up, he noted. Both residential builders and the banks that finance their projects might be hesitant at first to explore uncharted territory.

“Just by allowing something,” Freemark said, “doesn’t mean it’s going to be built immediately.”

In Arlington, some of the most critical details that determine how to build “missing middle” housing are not up for debate. For instance, these new buildings must conform to existing height limits and setbacks, which determine how far they must be from the edge of their lots.

But a dozen other details are still very much in the works — from what can be put on a lot and where it can be built to how many parking spots must be incorporated into the design and even where the doors on a duplex must go.

It appears likely that the Arlington County Board will approve some sort of “missing middle” proposal. Critics of the plan are pushing to either delay the vote or pass as narrow a version as possible. Proponents, meanwhile, have said that only the most extensive version will tip the scales such that home builders see the economic rewards of constructing “missing middle” housing instead of larger, single-family houses.

Below is a look at some of the key details that the board will vote on Wednesday as part of what is officially known as “Expanding Housing Options.” Arlington’s planning commission, as well as some other advisory bodies, voted on their own suggestions earlier this month, and county planners have made recommendations in all but four of the most controversial, politically charged areas.

The final decision, however, will come down to the five lawmakers on the board.

Maximum number of units

This piece of the “missing middle” proposal has taken up most of the conversation in Arlington so far. County planners initially proposed allowing small multifamily buildings with up to eight units on any residential lot.

But lawmakers narrowed that down to six during a preliminary vote in January and have the option to lower it even more. The proposal would also allow for semidetached houses and sets of up to three townhouses that face the street.

The Arlington chapter of the NAACP, one of several civic groups that have backed the “missing middle” plan, argued that a tighter limit on the maximum number of units would only further enable “unequal housing opportunities” in single-family neighborhoods that for decades kept out people of color. It has brought in the NAACP’s national general counsel to question the January vote.

Kathy Rehill, a Realtor and member of the group Arlingtonians for Our Sustainable Future (ASF) — a group that opposes the policy — said she thought that sixplexes would lead only to smaller, one- or two-bedroom units that are not missing from the real estate market. Given the high cost of new housing, these properties would not open up those areas to groups that have been historically excluded, she said.

Annual development cap

In response to concerns that “missing middle” housing will overwhelm Arlington, county board members are considering a cap that would limit the number of single-family lots that are turned into townhouses or multifamily buildings each year.

That cap could be temporary or permanent, and planners and lawmakers would still need to determine the exact number — it could go as high as 58 permits in one calendar year — and how to distribute those permits.

Rehill, who owns a four-bedroom house in the Donaldson Run neighborhood, said this limit will temper the impacts of “missing middle.” “The cap will give them time to work further on the details in a less politically charged atmosphere,” she said.

Hogan, the affordable housing advocate, said a cap was “antithetical” to the rest of the “missing middle” plan and its stated goals, especially given that “missing middle” housing is unlikely to pop up all at once.

An annual limit would discourage developers and bank lenders from taking the risks necessary to build small-scale multifamily housing in neighborhoods where it does not exist, she said. “The less we impose, the more likely we are to incentivize builders to do something else.”

Minimum site area

In some of Arlington’s residential neighborhoods, the smallest lots are 5,000 square feet, while in others, they are four times that size. For “missing middle” housing with more units, this category determines whether you can build on the smaller lots at all.

Many of the single-family lots closest to Metro stations in Arlington skew on the smaller end of things, so the minimum site area could determine how many units get built within walking distance to public transit. Lawmakers might set rules that would allow for more units on these “transit-proximate” sites and more restrictions farther away.

Harner, the architect, has advocated for allowing five- and six-unit buildings on all lots closer to Metro stops but only on larger lots everywhere else. This more conservative choice would make sure that the county does not “give away” smaller lots all at once, he said.

“If we start with the maximalist approach and let it go as a free-for-all, it’s going to be harder to pull back from there,” he said.

Rehill, meanwhile, supports an option that has the greatest limits for sixplexes across the board — not just far away from public transit — because they will mostly produce smaller one-bedrooms that already exist in the real estate market.

But Emily Hamilton, an economist at George Mason University’s Mercatus Center, is advocating for what she says is the most expansive choice: All “missing middle” buildings, up to six units, on any lot that allows for a single-family house. Absent tighter rules, “it leaves it up to the market to discover what works best for Arlington,” she said.


The big debate here is about sites that are close to a Metro entrance or bus stop: Should this new “missing middle” housing be required to have one off-street parking space for every two units, or no spaces at all?

Sites that are farther away from public transit would be required to have one off-street parking space per unit. Lawmakers could choose to lower that requirement on a case-by-case basis, depending on a parking survey that examines the current availability of on-street parking. (New construction on cul-de-sacs would still be required to have one spot per unit.)

Additional provisions could also remove the option for a parking survey or create an exception depending on the impact of curb cuts. If a “missing middle” site gets rid of more or the same number of parking spots on the street as it would be required to create on the lot, the site would be exempt from any requirement for new off-street spots.

Hamilton, the GMU economist, said that lower parking requirements, especially on smaller lots that tend to be close to the Metro, will make “missing middle” easier to build — there are less things to fit in more limited space.

“Where [it] makes the most sense is in the neighborhoods that are still walkable, still close to transit, still close to retail but a little farther out,” said Hamilton, who owns a three-bedroom apartment in a 13-unit building in Ballston.

But Harner said it is unrealistic to expect residents not to own cars.

“We just can’t wish away the requirement that people will need to park,” he said. “In the near term, the streets can accommodate a certain number of cars, but in the longer term as development takes place, that resource will be used up.”

Lot coverage

This term refers to how much of a given lot can be taken up by a “missing middle” building. The same limit exists for single-family houses in Arlington: This footprint of all structures must not exceed a certain percentage, and the rest of the lot must be left for greenery or other uses. The larger the lot, the smaller this percentage.

Builders who build detached garages or certain kinds of porches can boost their total building footprint by a small percentage.

Lawmakers will choose whether to extend the same bonuses to “missing middle,” but only for the main structure. So if a single-family house can take up 40 percent of a given lot by itself and 45 percent with a detached garage, a “missing middle” building on its own could take up 45 percent.

Hogan said the existing bonus serves as an incentive to house vehicles, and extending it to “missing middle” buildings would provide an incentive to house people instead.

“If we want to get away from car-centric development, and we want to incentivize better development into neighborhoods, it’s logical to disincentivize garages and use that instead toward more of the building itself,” she said.

Harner, however, suggested that the county could always add this option later as necessary. A similar set of rules governing single-family and “missing middle” housing would also allow county staff to better compare and study the two forms if a policy is put into place.