The First 'Missing Middle' Reform of the Year Has Passed. Will It Get Housing Built?

Arlington's successful passage of a modest missing middle housing reform bill after an intense debate raises the question of whether YIMBY politics can practically fix the problems it sets out to address.


After a long and often contentious fight in the Washington, D.C., suburbs, Arlington County, Virginia, has managed to pass the first "missing middle" reform of 2023. A policy unanimously approved by the five-member County Board will allow property owners to build at least four, and in many cases six, units on lots where only one home was allowed before.

Similar reforms have been passed at the state level in California, Oregon, and Maine. A half dozen other states are considering missing middle reforms this legislative session.

For Yes in My Backyard (YIMBY) advocates, it was another proof of concept that exclusionary single-family-only zoning can give way to a liberalized code that allows more affordable townhomes, duplexes, triplexes, and more.

"It unlocks about 75 percent of Arlington's residential land to new housing that isn't just the most expensive type of housing, that aren't just single-family homes," says Luca Gattoni-Celli, founder of the group YIMBYs of Northern Virginia. "Although the best time to plant a tree is 20 years ago, the second-best time is now."

Opponents of the reform decried the passage of missing middle, which has been in the works in one form or another since 2015, as a sloppy rush job that they would continue to fight by other means.

"We just made a decision based on emotional arguments, not on fact and analysis," David Gerk, a member of the group Arlingtonians for Upzoning Transparency, told The Washington Post. "Having not listened to the residents and rammed through a rushed plan, our next stops are the courthouse and the ballot box."

Striking a more measured tone than either proponents or detractors of the missing middle ordinance was Arlington County staff, who noted in a report before the vote that the policy options being considered by the board would not result in many drastic changes.

"Staff anticipates…that construction of [missing middle] development would occur gradually over time," they wrote. "Replacement of older single-detached houses with new, larger single-detached houses would still be the most common type of change experienced in lower-density residential areas."

To guarantee this, the county board voted to include a cap on the number of annual permits that could be for properties making use of the "expanded housing options."

Only 58 former single-family properties could have new townhomes and multiplexes on them, with additional sub-caps distributed by zoning district. The county staff report says that the overall cap is about one-third of the average annual permitting activity in Arlington's low-density zones.

This overall cap, and particularly the distribution of the cap amongst different zoning districts, could prevent a lot of development, says Emily Hamilton, an economist and housing researcher at George Mason University's Mercatus Center.

"The place where I think missing middle will make the most sense in a market perspective and a planning perspective is in Arlington's neighborhoods that are zoned for single-family but are nonetheless really close to Metro or other transit corridors," she says, Yet, only 37 permits for missing middle projects can go to smaller R5 and R6-zoned  lots near transit.

A number of other regulations in Arlington's ordinance will suppress production even further, says Hamilton. That includes parking mandates of up to one off-street space per unit, which she says will be particularly burdensome for four-to-six-unit homes, taking many of those units "off the table." The county has also set maximum floor plan sizes for multiplexes below the space allowed for some single-family homes, creating a further disincentive to build.

On paper, missing middle housing seems like it would be a relatively straightforward way for communities to enable more home construction without aggravating the anti-growth concerns of existing residents.

The type of housing being legalized is not all that different from the kinds of housing that already exist in low-density zones. Gattoni-Celli notes that Arlington's single-family neighborhoods are littered with existing, grandfathered-in duplexes and multiplexes that would be illegal to build today.

Katie Cristol, an Arlington County board member and early supporter of the missing middle reforms, describes them as intentionally "small 'c' conservative."

"The idea is based around the idea that a little bit more density can be built so long as it's in the form of a single-family home," she tells Reason.

The other side of this coin, however, is that the supply effects of such a small "c" conservative policy are quite modest. Other cities and states that have abolished single-family-only zoning have required that new duplexes and triplexes be roughly the same size as (or a little bigger than) single-family homes.

That really suppresses developers' desires to tear down existing single-family homes only to rebuild a similar-sized building of smaller units.

Hamilton says Arlington's requirement that new multiplexes be the same size as single-family homes isn't as burdensome in practice as other cities' policies.

The county already allows very large single-family homes to be built, housing is very expensive, and there are a lot of older single-family homes that are a lot smaller than they're legally allowed to be. A builder could make a lot of money taking one of those smaller homes and building a bigger, six-unit multifamily development, she says.

Even so, there's still the issue of the county's cap.

Cristol says there was no way the board would have approved the missing middle reforms without the 58-permit cap. She notes that she was the only "yes" vote on an amendment that would have gotten rid of the regulations further limiting how many of those 58 permits could go to which zoning districts.

Nevertheless, the intentionally incremental nature of Arlington's reforms didn't appear to do much to mollify opponents or lower the temperature of the debate. Almost every news article on Arlington's missing middle proposal has noted the emotions it's kicked up.

For months, the county has been covered with yard signs supporting and opposing missing middle reforms. Normally sleepy planning commission hearings became packed with crowds of activists on either side.

The Arlington County Civic Federation, a group opposed to the missing middle reforms, compiled a 108-page report alleging a lack of transparency and even improper collusion between county officials and pro–missing middle advocates. Arlington's YIMBYs countered with a press release accusing the opposition of harassing missing middle reform supporters in person and online.

"I don't think anything came close" to being this emotional, Cristol says, noting the relative tranquility about Amazon's HQ2 moving to the county.

Modest reform proposals being watered down in the face of strident opposition and then going on to produce little new housing has thus far been the story of recent missing middle reforms, where they've managed to pass.

Given the political lift they require and the limited number of units they produce, it's a fair question to ask whether these reforms are worth the effort expended on them.

Far from using up a fixed amount of political capital, Gattoni-Celli argues pursuing a reform that gets over the finish line was beneficial for the county's pro-housing forces. The fight helped activate and build a larger coalition that can more effectively fight the next housing battle. Both the Sierra Club and the local NAACP chapter supported missing middle.

"We really built the airplane as it was taxiing down the runway," he says. "This initiative was really great for our development and our maturation. Having a McGuffin, having something to go after, is really key."

He says his group is now looking to take on reforms in other Northern Virginia communities, including Alexandria and Fairfax.

Cristol, who is not running for reelection, says that she has serious concerns about the way the 58-unit cap is distributed across zoning districts and the regulatory uncertainty it will create. But she also says that, given how lucrative single-family home construction still is, the cap itself is probably pretty close to what the market would already produce. The cap also sunsets in 2028.

"It's hopefully putting Arlington on a different trajectory than the one that we were on now," she says. "We'll start to see opportunities like the one that gave my family a shot in Arlington, which was a 30-year-old condo in a largely low-density neighborhood. There's a lot of hope in the long run for that too."