Seattle’s Largest Down-Zone


Lots less than 3,200sf won't be able to be developed or raised above 18' tall (22' with sloped roof)

On the April 18th, there will be a final public hearing regarding small lot legislation, which is targeted for passage in early May. Although almost unnoticed by the media, and not acknowledged in presentation materials, “interim” legislation has already been passed that may have been the largest down-zone in Seattle’s history. The proposed permanent legislation will slightly lessen this down-zone, but will carry many features of the original interim legislation.


A few years back, developers started building houses on small lots in Seattle that were previously side yards or back yards. These houses were often tall, up to three stories in some case and built looking over yards. Inevitably, there was a public backlash from neighbors who were close to these developments. The City Council created emergency legislation to stop small lot building, and directed the Department of Planning and Development (DPD) to come up with a longer term solution.

Your humble writer made it to meetings early on, one of which was poorly attended (four attendees). At the time of the interim legislation, it appeared that the subject of the legislation was only about blocking small-lot developers from building new houses in side yards. It also seemed like the legislation was simply a minor code change. But my sensibility all the same was to oppose the legislation. Why? Density is density, even if it’s just a little bit.

Looking into this more recently, I realized that the implication of the new rules would actually impact a large number of homes, not just side yards. It turns out 45% of homes in SF5000 zones are on small lots. And, the legislation will effectively down-zone 7% of all single family homes in the city. Looking back, it’s amazing to think that very a small group of vocal critics could have such a dramatic impact on the future development of our city.

More after the jump.

Single-family zones

Over 60% of Seattle’s land area is taken up by single-family zoning. There are three categories for single-family zones: SF5000, SF7200, and SF9600. Smaller lot sizes are generally located closer in to the city center and larger lots further out. For instance, SF5000 is very common in Greenwood and the Rainier Valley, SF7200 in Lake City, and SF9600 in Fauntleroy. (The number in the zoning type indicates the standard minimum lot size.) However, 45% of all SF5000 lots are actually smaller than 5,000 square feet. Often, these properties were platted and developed before Seattle adopted a zoning code and tried to limit density in single-family neighborhoods. The 45% of SF5000 properties (as well as 30% of SF7200 and 20% of SF9600 homes) are all considered “small lots”.

The proposed legislation is a serious overreach from its original intent. It creates complicated rules regarding the calculation of lot size and adds everything from window locations to width-to-depth requirements. For example, when determining height, you accomplish this by drawing largest rectangle inside your lot. Height is strictly regulated and reduced from that of properties meeting the minimum lot size of the zone. This impacts property owners who already have homes in these zone.

In fact, building heights will be reduced for 7% of every single-family home in Seattle. Any lot that is under 3,200 square feet will only permitted 18 feet in height, or 23 feet in height with a pitched roof. An exception to this standard is permitted up to 27 feet in height with a pitched roof, but only if a house has very high ceilings. Of course, the second floor would necessarily be smaller in design or remove the option of a daylit basement. Before the interim legislation, the zoning code permitted residential structure 30 feet in height, or 35 feet in height with a pitched roof (remove 5 feet if it’s on a skinny lot).

Why this matters for urbanists and renters

Housing prices are going up in Seattle. In higher priced cities like San Francisco and New York, single-family homes tend to build out to their limits and rent out extra space. This provides enough income to the homeowner to afford the house, and increases density. Every new home in Seattle means one more household can afford to live here. And, as single-family homeowners provide additional units on the same lot, it eases the increase in housing prices.

However, if property owners are not allowed to build up to match their neighbors, they likely will not rent out space. 18 to 23 feet effectively only allows a one-story home, and at most a 1.5-story home, with the second story fitting in the peak of the roof. The 27-foot option all but removes the possibility of having livable space in basements. This is down from up to 30 to 35 feet, which easily fits a full three stories plus a basement. Reducing the ability to build up on 7% of our homes effectively removes hundreds of thousands or even millions of square feet of potential living space in the city, dropping density dramatically.

Why this matters for homeowners

If you live on a lot less than a 3,200 square feet in size, the maximum height has effectively gone from 35 feet down to 23 feet. That addition you dreamed of will never happen, and even if you never planned to expand your house, your home value just went down. The pool of buyers will look more favorably at your neighbor’s slightly larger lot, knowing that they can either build up or at least keep the value in case the next owner wants to build up. Even if the physical home you live in is the same, the potential square footage of your home just went down.

What you can do

There is still an opportunity to delay or block this legislation. It’s worthwhile to tell the Council that you want to repeal the interim legislation in full and table any further effort to proceed with permanent rules. While it may seem bold, going further to remove the lot minimums entirely is reasonable. Why deny the pattern language of small lots in Seattle when they are the norm, not the exception? Let’s go back to the way our houses were built back in the early 20th century: small lots and all.

A public hearing is scheduled on April 18th at 2pm with the Planning, Land Use, and Sustainability Committee. Please be sure to attend that hearing and share your opinion if you have time. Otherwise, you can always contact Council Member Mike O’Brien. The Council is expected to vote on a bill in early May.

Article Notes: Greater than 60% of zoned land in the city is designated as Single-Family per data from DPD (to be precise, that number is 64.8%, compared to 11% for all multifamily zones combined).

The 7% number and lot size numbers were derived from an e-mail by DPD planner Andy McKim:

“Of the tax parcels in SF 5000 zones, 55% are 5,000 square feet or larger, and the rest are smaller. In the SF 7200 zone, about 70 percent of the tax parcels have areas of at least 7,200 square feet, and in the SF 9600 zone, about 80 percent of the tax parcels have an area at least 9,600 square feet….Lower height limits would apply to lots under 3,200 square feet in area, which we estimate to be about 7 percent of the lots in SF zones.”

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How many 3200 sq ft and below lots are in the city?

Paul Conte

I co-founded and -chaired the “Infill Compatibility Standards Task Team” in Eugene, Oregon and have done a lot or “grass roots” community work on infill. I wrote the code (based on community direction) for the first (and only) two zones that have infill standards.
I don’t know the author’s broad views on infill, zoning and the dynamics of neighborhoods, “sprawl,” etc., but one thing jumped out — “Density is density …,” which I took as a implying all density is good. That’s a HUGE mistake, as anyone who has considered the implications would have figured out.
It also wasn’t clear what the historical development limits and actual development pattern were on these “small lots.” It is morally and pragmatically a very bad strategy to impose a dramatic change in zoning on a neighborhood community unless there’s broad and well-informed community process that seeks the change. (I’m not talking about civil rights issues. This is about building heights, density, etc.)
If three stories above a tall foundation on “small” lots was the law and the norm as a neighborhood was built out, then an owner should have no complaint if a vacant “small” lot is developed that way. But conversely, if the build-out was 1-1/2 stories and the code is being aligned, then density fanatics shouldn’t impose their “wiser” perspective on the established community.
Dropping down to a tactical level, two very effective, but seldom used, tools to deal with the issues of privacy, solar access, crowding, etc. between adjacent and nearby neighbors are: a) sloped or stepped setbacks (higher structures have greater setbacks); and b) “fungible” setback space (IOW, allow easements to be granted for sloped/stepped setbacks in three dimension).
We implemented both concepts in the zones I mentioned. You can learn more about these and other ideas in this document:

— Paul

Paul Conte

Thanks for the thoughtful response.

I’m not doubting your word, but are you sure you have the full and accurate history of these lots? In many cities, the inner neighborhoods (once the outer) were zone in the 30’s (plus or minus) and, if they were “single-family,” often had some basic restrictions (lot size and height commonly).

However, if the area was built-out under zoning that allowed small lots and three stories, then that’s reasonable to allow to continue.

I think you would realize that “every new home in Seattle allows another household to _afford_ to live here ” is true only if you aren’t concerned about cost. It’s certainly _not_ true that “every new home in [name your city] allows another household with at least median income to _afford_ to live here.”

Further, it’s quite clear that building new dwellings can _exacerbate_ “sprawl” if it destabilizes neighborhoods. Aspen is an extreme example. Eugene is also a good example, where lower income households and households who’ve seen their neighborhoods degraded by thoughtless student housing have “fled” to outlying towns that are an easy commute.

This is a much more complex system than “increasing density diminishes sprawl” reflects.

— Paul

mike eliason

I find this to be both alarmist, and misleading. To begin with, nothing has been approved, so nothing’s been downzoned.

Let’s look at the facts without wearing the Valdez misdirection hat. 7% of lots in Seattle are under 3200 SF, but lots that are under 30’ in width are ALREADY effectively ‘downzoned’ under current LUC – having a height limit of 25’ w/ a 5’ sloped roof bonus. So in order for 7% of all single family homes to be ‘downzoned’, the assumption has to be 100% of those houses are not already under 30’ in width – and I can tell you that’s just not anywhere near true. So if you lived on a lot under 3200 SF that’s less than 30’ in width, there was no ‘effective downzone’. Second, a number of existing homes on these lots were already at or close enough to height limit another story can’t be added – so they didn’t get ‘downzoned’ either.

Lots under 3200 SF aren’t limited to 18’, but rather 22’ – if the FIRST floor is 10’ in height. Plus then the 5’ bonus. If you can’t fit 2 floors and a crawlspace in 27′ – then you’re just not being very creative. One a flatter lot, you could fit 2.5 floors.

The width-to-depth requirements are ONLY for buildings taking the ‘historic lot exemption’.

Additionally, the assumption here that homeowners would have added ADUs before this legislation ‘effectively downzoned’ them just doesn’t hold any water. The total number of permitted ADUs across all SF zones in TWENTY YEARS is low, less than 2000 units or 1.5% of all eligible lots. Since ‘94, land and housing costs have more than doubled. Most people bought their homes before the bubble peaked, so their housing costs are no where near the costs of new construction – their need to add ADUs for affordability is nearly non-existent. And the council has added practically zero incentive to add them. Those that would add ADUs haven’t because of the onerous owner occupancy requirements and off-street parking requirements.

The SF zones could easily triple the number of units. Fighting for piecemeal ‘density’ with new construction rather than pushing for density increases in the SF zones just doesn’t make any sense to me. Duplexes, triplexes, rowhouses, zero lot line construction, removing owner-occupancy requirements for DADU/ADUs, allowing both DADUs and ADUs on single parcels – any or all of these would add significantly more units.

Fight for that, fight for actually making a difference with regards to density and affordability in the SF zones. Don’t spout misleading talking points that will only further divide the community and get regurgitated by blogs with ulterior motives.

Also, I know it’s a diagram, but it’s still not correct – the inner house couldn’t build to the same height as neighbors anyway (lot’s too thin).


Do you have links to any examples of structures that had been built under the existing code, particular the ones residents found offensive?


Sorry, I wasn’t clear with that question. I meant new structures (on side yards, say) built under the current code that allows them. But understood about photos of homes. I’d like to see what we’re considering allowing/prohibiting, but that’s a valid point.


Great reply. Thanks.