Architecture
Unlocking Seattle’s New Zoning Code for Homeowners
Seattle’s new zoning code gives homeowners far more options for their own lots. Even with more updates on the way, changes that took effect in January 2026 already allow housing types and design approaches that weren’t permitted before. Here’s what changed, who benefits, and what the new Neighborhood Residential standards allow.
October 13, 2026
As of January 21, 2026, Council Bill 120993 updated the Seattle zoning code to allow more housing in Neighborhood Residential and Lowrise zones. The changes implement Washington State House Bill 1110, which legalized “missing middle” housing across the state.
What changed in the Seattle zoning code.
Seattle’s land use code now groups the former Neighborhood Residential 1, 2, and 3 zones and the Residential Small Lot zone into a single Neighborhood Residential zone, with more flexibility in how a lot can be developed. On a 5,000 square foot lot, it is now possible to build four to ten dwelling units, depending on how they are configured and other aspects of the project. More permissive floor area, setback, lot coverage, and height standards make room for those additional units. The specific standards are outlined at the end of this post.
Who can benefit from the zoning changes?
The Neighborhood Residential update may change who builds new housing as well as what gets built. Historically, Seattle allowed multifamily development mainly in and around neighborhood centers. Lots zoned for apartments and condos were fewer and larger, so large apartment buildings were often the only projects that were allowed or made financial sense. Projects at that scale generally require an established real estate developer with significant capital. Now, homeowners with ordinary residential lots have a real path to adding units themselves or partnering with developers or investors to do so.
There are many ways to use the new code. Here are a few scenarios:
- A family buys a lot to build their primary home along with a couple of additional dwelling units, using the relaxed setback and height standards to tuck the extra units along the sides of the lot or beneath the main house. Over the years, those units can house adult children or visiting guests, or be rented out.
- An empty nester wants to downsize without leaving their neighborhood. With few smaller homes for sale nearby, they redevelop their property as a cottage housing cluster: a house sized to their needs, plus additional dwellings to rent for income in retirement.
- An existing house is divided into multiple units to rent or sell. A 3,000 square foot house, for example, could potentially be converted into four or five dwelling units.
- A developer combines two adjacent 5,000 square foot lots to build 20 stacked flats, using the higher density allowed for projects that retain trees or meet Green Factor goals.
The details: what’s now allowed in Neighborhood Residential zones.
Maximum Floor Area
Floor area ratio (FAR) caps a building’s total floor area as a ratio of the lot area. Under the new code, allowable floor area is tied to the number of dwelling units on a lot, so building more units unlocks more floor area.
Floor area ratio limits
- Density below one unit per 4,000 square feet of lot area: 0.6 FAR
- Density from one unit per 4,000 square feet to one unit per 2,201 square feet: 0.8 FAR
- Density from one unit per 2,200 square feet to one unit per 1,601 square feet: 1.0 FAR
- Density of one unit per 1,600 square feet or greater: 1.6 FAR
Floor area ratio bonuses
- Cottage housing (structures under three stories arranged around a courtyard): 1.8 FAR
- Stacked flats at a density of one unit per 1,600 square feet or greater: 1.8 FAR
- Stacked flats that retain a Tier 1 tree, retain two Tier 2 trees, or meet a Green Factor score of 0.6: 2.0 FAR
- Certain buildings within one quarter mile of an elementary or secondary school: additional FAR
The code also encourages accessible design. In stacked buildings with fewer than ten units, units built to Type A accessibility standards do not count toward FAR.
Maximum Number of Dwelling Units
The base density limit is one dwelling unit per 1,250 square feet of lot area. On a 5,000 square foot lot, a typical Seattle lot size, that allows four units. Every lot, including those smaller than 5,000 square feet, is allowed at least four units. On lots with environmentally critical areas, such as wetlands, creeks, or steep slopes, allowed density is reduced in proportion to the share of the lot those areas cover.
Several scenarios allow more than four units:
Stacked flats
- Stacked flats: one unit per 600 square feet of lot area
- Stacked flats that retain a Tier 1 tree, retain two Tier 2 trees, or meet a Green Factor score of 0.6: one unit per 500 square feet of lot area
Lots near major transit or with affordable units
Up to six units are allowed if the lot is within one quarter mile of a major transit stop or if at least two of the units are affordable.
Courtyard housing in frequent transit areas
Structures under three stories arranged around a courtyard are allowed one unit per 650 square feet of lot area.
Accessible dwelling units
Type A accessible dwelling units, which are designed to a high level of accessibility, do not count toward maximum density.
Maximum Height
The base height limit is 32 feet, plus allowances for pitched roofs. The limit increases to 42 feet when a project meets any of the following:
- Three or more principal dwelling units with a front setback of at least 20 feet
- Stacked dwelling units with a Green Factor score of 0.6 or higher
- Retention of a Tier 2 tree
- Tree planting or preservation that will reach 10 percent canopy coverage at maturity
- Stacked dwelling units within one quarter mile of an elementary or secondary school, where at least 25 percent of the units have three or more bedrooms and at least 1,050 square feet
Roof elements such as gables, sheds, and parapets may extend a set distance above the height limit.
Maximum Lot Coverage
Structures may cover up to 50 percent of the lot, reduced in proportion on lots with environmentally critical areas. Any structure, deck, or porch more than 36 inches above existing grade counts toward lot coverage. Higher coverage is allowed in these cases:
- Structures under three stories arranged around a courtyard: 60 percent
- Stacked flats: 60 percent
Type A accessible dwelling units do not count toward lot coverage.
Setbacks
Setbacks are more relaxed under the new code. The biggest change is at the rear of the lot, where the required setback dropped from 25 feet to 15, 10, or 5 feet depending on the project.
- Front setback:
- Lots with one or two dwelling units: 15 feet
- Lots with three or more dwelling units: 10 feet
- Rear setback:
- Lots with one or two dwelling units: 15 feet
- Lots with three or more dwelling units: 10 feet
- Lots under 5,000 square feet in frequent transit service areas: 5 feet
- Lots where the rear abuts an alley: no setback required
- Side setback:
- Lots under 5,000 square feet in frequent transit service areas: 3 feet
- All other lots: 5 feet average, 3 feet minimum
Amenity Areas
Every unit must have access to a shared or private outdoor amenity area. The required amount is:
- Stacked dwelling units: 25 percent of the lot area, or 20 percent if every unit has a balcony
- Attached and detached dwelling units: 20 percent of the lot area
No amenity area is required when adding one new unit to a dwelling that existed as of 1982 or to a multifamily building that existed as of 2001. Projects that meet certain tree retention criteria are also exempt.
Parking Requirements
In some cases, one parking space on site is required for every two dwelling units. No parking is required for lots within a half mile walking distance of a major transit stop, such as light rail, commuter rail, or bus rapid transit, or for lots within a Station Area Overlay District or an Urban Center in a frequent transit service area. Parking is also not required for dwelling units of 1,200 square feet or less, accessory dwelling units, housing for lower income households, or housing for seniors or people with disabilities.
Why the right partners matter.
The new code is more permissive and more detailed, and Seattle property owners are eager to build under it. Permitting under the new rules is still unfamiliar territory, though, for homeowners, City of Seattle reviewers, and designers alike. Board & Vellum can help with site evaluation, permitting, and connections to trusted contractors and consultants. Our predesign services include feasibility studies: detailed reports that describe what your site can support, tailored to how you hope to use the property.
Thinking about what your lot could support? Let’s talk.
