This spring, California toyed with passing SB 827, an ambitious zoning preemption bill authored by State Senator Scott Wiener that would have allowed five-story apartment buildings within walking distance of high-frequency mass transit stops. Many Bay Area Rapid Transit (BART) stations and a good number of LA Metro stops are surrounded by low-density single-family zoning, which limits transit access and squanders those sizable investments. That bill ended up dying an early death in its first committee hearing in April, but the idea inspired housing advocates. It also paved the wave for a scaled down version applying only to BART stations that California Governor Jerry Brown signed Sunday.

It appears Washington state legislators may attempt to pick up the torch from California and pass a bill pushing zoning friendly to transit-oriented development.

State Senator Guy Palumbo (D-Maltby) provided The Urbanist with an early draft of “minimum density” legislation and has been distributing it around to local planning departments and other stakeholders in the Puget Sound Region. Areas of Washington state meeting the bill’s requirements would no longer be allowed to have big-lot single family zoning. Instead the bill would set up a tiered minimum zoning around rapid transit station and explicitly allow duplexes, triplexes, fourplexes, townhomes, and courtyard apartments (5 to 12 units), single-room occupancies, and accessory dwelling units (with no ownership requirement.)

Fine-tuning the Growth Management Act

The bill would push municipalities and counties to follow the spirit of the Growth Management Act (GMA) and encourage the region to build up rather that out. Passed in 1994, the GMA has been a check on suburban sprawl on the periphery of the Seattle metropolitan region; although plenty of suburban-style big-lot single-family housing has continued within the GMA’s borders. To make matters worse, some cities and neighborhoods within the GMA are taking very little growth. In fact, many predominantly single-family neighborhoods in booming Seattle actually have shrinking populations according to a Sightline Institute analysis.

The difficulty in adding urban-style housing in a region that is aiming to curb suburban sprawl has led to a situation where it’s hard for young people to get off the hamster wheel of every increasing rent checks and little prospect of saving enough to buy a home–even a modest backyard cottage or a small condominium. And because so much new housing is high-end apartments in high-cost neighborhoods, people who are looking for more affordable housing don’t have many options. Well, beyond drive until you qualify suburban single-family homes.

Maltby, Epicenter of Growth?

“At a high level, if Seattle was taking enough growth, we’d have downward pressure on prices,” Senator Palumbo said, adding the result is “massive problems in South Snohomish and in North Pierce County.”

Senator Palumbo represents the 1st legislative district (LD-1) which spans a wide cross-section of northwestern suburbia picking up Bothell, sections of Kirkland and Mountlake Terrace, and unincorporated communities like Maltby, North Creek, and Echo Lake.

“In D1 we’re at the epicenter of Seattle not taking growth,” Senator Palumbo said. “Everybody has to drive to qualify because they can’t afford to live in Seattle. People are getting pushed out father. Lake Stevens, Marysville, Arlington…”

“The GMA is breaking and we have to do something about it.”

Senator Palumbo said he started the conversation last year when he brought a bill (SB 6077) setting a minimum density of six dwelling units per acre across municipalities to his colleagues, but they deemed it too broad. He went back to the drawing board and tried to find a mechanism that would more specifically tailor the minimum density requirements. After looking at using a threshold based on the median home price, he determined it was hard to get good data at the municipal level, he said. Instead Senator Palumbo settled upon a trigger similar to the California’s SB 827 using proximity to transit.

Defining High Capacity Transit

“This time around we took a TOD focus,” Senator Palumbo said. The idea here is that areas with frequent transit access should allow transit-oriented development or TOD. The early draft legislation would affect a broad swath extending a mile in each direction from transit stops, although Senator Palumbo said how high to set levels and how far to extend the minimum density requirement would be negotiated and hammered out before the bill makes it to the floor.

Everett is a city with big TOD plans around its future Link station. (City of Everett)
Everett is a city with big TOD plans around its future Link station. (City of Everett)

First, the draft bill would use rent burden–defined as a household with monthly housing costs, including utilities, exceeding 30% of its household income–to trigger the minimum density mechanism. If more than 20% of households in a municipality are rent burdened, then the minimum density requirement would apply–at least if the city has any qualifying transit corridors.

Some may fear that a rent burden threshold would upzone low- and middle-income areas and let some high-income enclaves off the hook, but Senator Palumbo said that’s not the intent. Moreover, virtually all Puget Sound Region cities would presently meet the rent burden threshold, given our sky-high housing prices.

“We wanted a reasonable trigger and felt that rent burden was fair,” Senator Palumbo said, adding he wanted to “increase density where working folks can’t afford to rent a place.”

The draft bill does not define what high capacity transit is, but Senator Palumbo expects the final bill will. One definition he suggested was rail or bus service with frequency of 15-minute or better. Whatever is settled upon it will be best to have an airtight definition with little doubt to be exploited in an appeal. Seattle’s experience has showing that a frequent transit definition can be twisted by anti-development activists so almost no bus line lives up to the standard–at least without a long appeal process.

If the bill does not define high capacity transit, it would be up to the Washington State Department of Commerce to define.

To help deal with the costs associated with implementing the minimum density requirements, the draft bill would create a state grant program of up to $10 million per biennium to which municipal and county planning departments could apply for financial support.

Density Wedding Cake around Transit

The draft bill sets up tiers of zoning to raise the level of density possible near rapid transit. The 1/4 mile radius around qualify transit stations would need to allow significant density and the effects of the bill would stretch a mile out from transit stations. The proposed breakdown is as follows:

  • 1/4 mile radius would need to allow 150 dwelling units per acre;
  • 1/2 mile radius would need to permit 45 dwelling units per acre;
  • 1 mile radius would need to allow 14 dwelling units per acre.
Single family homes can coexist with denser mulltifamily housing types. (Opticos Design)

While the density bill could be a political football, Senator Palumbo said he wants to learn from his mistakes last time around.

“I can see how many people have different goals they want to achieve in this bill,” Senator Palumbo said. “My goals are narrow. One, make meaningful progress on increasing supply, and, two, center it around transit. Having been through this last year, I am okay with getting a meaningful incremental win versus no win. Some have suggested just doing a city-wide density requirement which, while ideal, is basically my bill from last year that couldn’t get out of committee. So I am trying to keep it TOD-focused because there simply isn’t a good argument against that density.”

Missing Middle Housing

“Missing middle is the key component,” Senator Palumbo said. “We need those affordable starter homes, triplexes, duplexes. They’re not zoned and they’re not being built.”

Missing Middle housing types. (Opticos Design)
Missing Middle housing types. (Opticos Design)

Seattle is adding tons of apartments, but the bulk of that growth is highrise and midrise development. Missing middle housing types are a small fraction of Seattle’s growth, and Senator Palumbo sees that as a problem, because he believes the region has pent up demand for single-family homes and condominiums and consumers prefer the smaller scale that missing middle offers.

“People want to buy single family homes,” Senator Palumbo said. “There are plans to put 20,000 people in Everett rather than Southwest Snohomish, but people aren’t moving to multifamily in Everett, they’re moving to single-family in Southwest Snohomish.”

Everett does have ambitious plans to densify its downtown, but Senator Palumbo is correct Everett’s rate of redevelopment has been rather modest thus far. Between 2010 and April 2018, Everett gained about 8,000 residents. Perhaps as light rail nears, Everett’s plans will bear full fruits, and ditto for other suburbs with city center hopes like Lynnwood and Shoreline.

In the meantime, a bill like Senator Palumbo’s could help fill in the gaps and zone for a greater variety of housing types.

The status quo is beginning to appear untenable as housing prices rise behind the means of most young families. At the same time, investment in social housing is falling well short of what’s needed.

Senator Palumbo frames his bill as a fix for a failing GMA law: “If we’re not going to do this, the GMA is not going to work.”

Whether that’s true or not, the minimum density bill certainly seems like an improvement.

We hope you loved this article. If so, please consider subscribing or donating. The Urbanist is a 501(c)(4) nonprofit that depends on donations from readers like you.

Doug Trumm is The Urbanist's Executive Director. An Urbanist writer since 2015, he dreams of pedestrianizing streets, blanketing the city in bus lanes, and unleashing a mass timber building spree to end the affordable housing shortage and avert our coming climate catastrophe. He graduated from the Evans School of Public Policy and Governance at the University of Washington. He lives in East Fremont and loves to explore the city on his bike.

Inline Feedbacks
View all comments

I’m just getting up to speed on this, but the part that stood out to me was the rent-burden trigger. It seems wrong to apply this at a municipality level given that many families who can’t currently afford to live there have probably been driven to neighboring (if they are lucky) municipalities. It seems like it should be regional?

[ Or perhaps this threshold is easily achieved and I shouldn’t worry about it ? ]

Anthony Hope Marris

A few thoughts on this:

Developers *may* build at a lower density than allowed or would be feasible in the near future, but if they build anything at all it will still be denser than what’s there now, and the land wouldn’t have to sit vacant or underdeveloped in the interim. I think the kind of speculation being discussed could also be a factor, but I don’t know enough to make a judgement about that.

I do think this bill needs to take account of different market pressures throughout the region. 150 DU/acre might be the right call next door to Lynwood light rail, but I don’t know of any project in South King that reaches that level and zoning for it would makes heads explode.

One other thing to consider is the 1-mile radius. Not only is it too large, it’s not the right way to measure access. Two points here: 1. We have amazingly powerful tools at our disposal for network analysis, and can create walkshed models that take things like geography into account so we’re not upzoning next to some 12% grade that pedestrians barely use, and 2. Upzoning a 1-mile radius around current and future RapidRide stops in Renton results in virtually the entire city getting upzoned. Even with a tiered approach, that’s simply not going to happen and I think we need to be more strategic politically.

The bottom line for me is that zoning for more density is a political nightmare virtually anywhere in the region, and it would be a shame if NIMBY opposition is emboldened by over-ambition. This is a good policy in theory but it needs a lot of refining at a more granular level to have any chance of success.

Andres Salomon

Regarding the 1mi radius: Time and time again, NIMBYs have proven that they’ll fight anything and everything. Quads in Minneapolis? Yep. Backyard cottages in Seattle? Lawsuit. Expensive market-rate housing downtown for tech workers? Sure. Housing out in the edge of Seattle for poor people? A decade of lawsuits.

It would be foolish to assume that they won’t fight this, but at the same time compromising from the start makes concessions later on even more painful. Go big, and scale back if necessary.

Anthony Hope Marris

I agree, and I’m definitely not suggesting that this isn’t worth doing. But we’re already hearing feedback that NIMBYs here may put pressure on transit authorities to keep service frequency below the 15-minute threshold laid out in the draft bill to prevent their neighborhoods from being affected. Someone has already created a map showing how much of the city would be upzoned if a mile radius requirement is imposed:

I think this is a great tool and we should absolutely pursue it (and perhaps add an affordable housing provision while we’re at it). But I don’t see how it makes sense to hand the opposition this talking point at this early stage when the final iteration of the legislation will very likely have different requirements spelled out to address the specific needs of each city. I’m not saying we shouldn’t expect opposition, only that we shouldn’t shoot ourselves if the food by emboldening it.


palumbo’s draft bill has a *minimum* required density. there would be a
rule saying you must build at LEAST 150 dwelling units per acre. if the
most that has ever “penciled out” in a certain geography is 115
dwelling units per acre, that’s not going to change because of this
law. i hypothesize that the land would sit vacant until 150 dwelling units per acre became
reasonable due to, presumably, rising land cost over many years.

Stephen Fesler

The draft bill would require jurisdictions to allow for a minimum density of designated areas by zoning, not that a development would have to achieve said density.


The danger with this approach: transit accessible land will get filled up with fairly low density development, precluding higher density development if that becomes feasible later.


as a municipal planner in south king county, i think the bill raises some interesting questions but leaves a bit to be desired in terms of implementability. i had the chance to review an early draft and thought others might find the following relevant:

1. the jurisdiction i work for has no minimum density in the zoning districts around high capacity transit (HCT) (and we have quite a bit of HCT) – yet, the highest density we’ve EVER seen has been lower than Palumbo’s proposed 150 du/ac. this suggests that the market does not yet support the level of density proposed, at least in south king–could function as an effective moratorium on development where we need it most. that’s counter to the point of the bill. might there be a way to account for market factors? a challenge, but may be necessary to address.
2. the bill includes language about “revising impact fees to reflect the different impacts of various sizes of types of single family” – this seems like a great idea but would require MUCH more detail to be implementable. impact fees can be extremely political and sometimes quite arbitrary – there are few agreed upon objective ways to calculate impacts (depending on which type you consider – some may be more calculable than others). much work would be required to determine different tiers of level of impact for different sizes AND for each type of fee assessed (fire, transportation, school, park). who will do this work? local jurisdictions are not equipped.

i hope this bill will go through some refinement and be checked against the varying market realities across the region – and then i look forward to implementing it. local jurisdictions need the political cover to upzone, in many cases, and state law CAN provide that. but it has to make sense. i look forward to some version of this passing in the coming years.


the jurisdiction i work for has no minimum density in the zoning districts around high capacity transit (HCT) (and we have quite a bit of HCT) – yet, the highest density we’ve EVER seen has been lower than Palumbo’s proposed 150 du/ac. this suggests that the market does not yet support the level of density proposed, at least in south king–could function as an effective moratorium on development where we need it most.

How do you figure that zoning to allow more density than the market will support would act as a moratorium on development? If your city is zoned for 20-story buildings but the market says five-story buildings are the most profitable, wouldn’t five-story buildings still get built?

There’s no rule saying you must build to the maximum allowed by zoning; we’ve just gotten used to seeing most parcels developed this way because much of our area is tragically underzoned.


The only theoretical argument I can imagine is something like “if the landowner thinks that the land only supports five story buildings now but will support twenty story buildings in ten years, and has some kind of time horizon in decades and calculates depreciation, it might make sense to wait and build nothing until the market supports the twenty story density to maximize profits over fifty years, whereas if the zoning were lower they’d build it right now.”

I don’t buy that argument at all, I think it’s counter to what actually happens. In loosely zoned areas people do not immediately build to the maximum zoning; they will often build to intermediate zoning levels.

Anthony Hope Marris

Late to the party here, but I think you’re correct that this would be the counterargument. I’m not so sure that it’s all that outlandish. I see precisely this kind of speculation all the time in South King County and I would argue it absolutely does restrict the supply of housing. In my city we have a slew of property owners who sit on underdeveloped properties because they are waiting until values are commensurate with what is allowed by zoning. Particularly for larger developers, it makes far more sense to build a 6 story mixed use building in, say, 5 years than it does a 3 story building now.

I think the situation you are describing is much more common, but in my opinion it happens too often to discount it when considering this legislation.


I do think that some developers wait to build on parcels until the expected profit is high enough, but I’m unconvinced that they’d be more likely to build to intermediate levels with lower zoning if the intermediate levels don’t meet their minimum profit margin. In my experience, in those cases, particularly for larger developers, they wait for five years and then petition for a zoning variance or zoning change.

The sorts of developers who do those calculations are the same developers who have the savvy and patiences to get individual zoning changes. The developers who just take the zoning as written (at least where I’m from) are the small developers who don’t have the portfolio to let things lie fallow and are more likely to build to intermediate levels anyway.