SEATTLE’S NEIGHBORHOOD RESIDENTIAL LAND-USE UPDATES 2025 - PART 1

Seattle is making big changes to its Neighborhood Residential (NR) zones to encourage more housing diversity and density—especially middle housing types—in response to Washington State’s House Bill 1110, passed in 2023.

These changes are being implemented in phases. On June 30, 2025, Seattle City Council passed Council Bill 120969, an interim zoning update intended to bring the city into compliance with HB 1110. This interim legislation was necessary because Seattle missed the deadline to update its Comprehensive Plan and zoning code.

While additional updates and amendments are expected as the full Comprehensive Plan results are finalized into the zoning updates later in 2025, the interim changes introduced by Council Bill 120969 are already in effect. So it's worth understanding what’s changed now.

The interim zoning code update introduces modifications in five key areas of Neighborhood Residential zoning:

  • Density Limits – Sets the minimum and maximum number of units allowed per site based on zoning.

  • Lot Coverage – Determines how much of the lot can be covered by structures (typically anything over 36” tall counts).

  • Yards (Setbacks) – Specifies minimum required distances between buildings and property lines (front, side, and rear).

  • Floor Area Ratio (FAR) – Regulates the total buildable interior floor area, including walls and stairs, relative to lot size.

  • Maximum Height – Limits building height based on the average grade plane, which considers the site’s topography.

We break down each of these components in more detail below. PLOT will publish a follow-up once the full zoning updates go into effect later in 2025.

(SMC 23.44.017) density limits

  • Before June 30th 2025

    • NR zones with lots over 3,500 sf - 1 primary unit plus ADU, and 1 Detached Dwelling Unit (ADU), for total of 3 units maximum

  • After June 30th 2025

    • At least four units on all residential zoned lots. This does not necessary mean 4 separate structures.

    • At least six units on residential lots within a quarter mile of major transit stops (such as light rail and bus rapid transit).

    • At least six units on residential lots if two units are income-restricted affordable housing.

      As defined in the HB, residential zones must support middle housing as “buildings that are compatible in scale, form, and character with single-family houses and contains two or more attached, stacked, or clustered homes including duplexes, triplexes, fourplexes, fiveplexes, sixplexes, townhouses, stacked flats, courtyard apartments, and cottage housing.”

    The increased density limits will likely be adjusted in the next phase of the zoning code update, but even now, this section represent one of the most significant changes for property owners in Neighborhood Residential zones.

(SMC 23.44.010) Lot Coverage

Before June 30th 2025

  • Lots that are equal or greater than 5,000 square feet: 35% of the lot area. Lots the are abutting an alley use the centerline of the alley, which increases the amount of developable area.

  • Lots that are less than 5,000 square feet: 15% of lot area + 1000 square feet

After June 30th 2025

  • Lots that are equal or greater than 5,000 square feet: 35% of the lot area. Lots the are abutting an alley use the centerline of the alley, which increases the amount of developable area - No Change

  • Lots that are less than 5,000 square feet: 15% of lot area + 1000 square feet - No Change

  • 50% of the lot area for any lot that has two or more detached dwelling units (primary dwelling unit and detached accessory dwelling unit).

This change will potentially allow more units on site.

(SMC 23.44.014) yards/lot setbacks

Before June 30th 2025

  • Front Yard: 20 feet or the average of neighbors (which can’t be less than 15 feet)

  • Side Yard: 5 feet

  • Rear Yard: 25 feet or 20% of the lot depth if the lot is less than 100’ depth.

After June 30th 2025

  • Front:
    • Lots with one or two dwelling units: 15 feet
    • Lots with three or more dwelling units: 10 feet

  • Rear:
    • Lots not abutting an alley with one or two dwelling units: 15 feet
    • Lots not abutting an alley with three or more dwelling units: 10 feet
    • Lots abutting an alley: no rear yard

  • Side: 5 feet (no change)

    New updates allows more flexibility on the setbacks and it’s dependent on how many units are on the site. This will allow more sites to be usable for multiple units developments.

(SMC 23.44.011) Floor area ratio

Before June 30th 2025

  • FAR 0.5 of the lot area

Exemptions:
• Areas below grade (less than 4’ between grade)
• Accessory Dwelling Units
• 500 square feet of detached accessory structure (such as a garage or garden shed) or 250 square feet for an attached garage

After June 30th 2025

• 1 dwelling unit per 4000 square feet or greater: 0.6 of lot area
• 1 dwelling unit per 2,201-4000 square feet: 0.8 of lot area
• 1 dwelling unit per 2,200-1,601 square feet: 1.0 of lot area
• 1 dwelling unit per 1,600 or less: 1.2 of lot area

Exemptions:
• Areas below grade (less than 4 feet between grade and ceiling)
• Common walls separating individual attached dwelling units

DADU’s & ADU now count in FAR calculations, but with increase to the ratio results in larger possible maximum floor areas, so it is a net gain for density.

(SMC 23.44.012) Maximum Height

Before June 30th 2025

  • 30 feet plus 5 foot additional exemption given to gable roofs with a pitch of 4:12 or greater, or 4 foot for a shed roof that extends past the max height.

After June 30th 2025

  • 32 feet with a 5 foot additional exemption given to gable roofs with a pitch of 4:12 or greater, or 4 foot for a shed roof that extends past the max height.

Gain of 2’ for towards the maximum structure height.

What does this mean for your site?

These updates gives property owners greater flexibility to utilize their neighborhood residential sites for additional housing units—helping to address housing demand and affordability while also increasing income potential.

Learn how PLOT can assist you in discovering your properties potential.

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