Seattle Zoning Overview

Seattle is the largest city in Washington with approximately 737,015 residents, located in King County. The city manages land use and development through its zoning code, administered by the Seattle Department of Construction & Inspections (SDCI). Seattle's zoning divides the municipality into districts regulating permitted uses, building heights, lot sizes, setbacks, and density.

Seattle follows the Washington State Building Code (WAC 51-50/51), which is based on the International Building Code (IBC) and International Residential Code (IRC).

Primary Zoning Districts

Seattle's zoning code includes several single-family residential districts. The SF5000 district requires a minimum lot size of 5,000 square feet with a 30-foot height limit and setbacks of 20 feet (front), 5 feet (side), and 25 feet (rear). The SF7200 district requires 7,200 square foot minimum lots, and the SF9600 district requires 9,600 square foot minimum lots, both with similar height and setback standards.

The LR1 and LR2 (Lowrise) districts accommodate multifamily housing including townhouses and apartments at varying densities. Commercial needs are served by the NC (Neighborhood Commercial), C1 (Commercial 1), and C2 (Commercial 2) districts, which support retail, services, and mixed-use development. The IG (Industrial General) district provides for manufacturing and warehousing uses.

ADU (Accessory Dwelling Unit) Rules

Seattle allows ADUs (Accessory Dwelling Units). Under Washington state law HB 1337 (2023), cities are required to allow ADUs, with up to 2 ADUs permitted per lot in most areas. This is a state mandate that applies to all Washington cities. Seattle allows both attached and detached ADUs. Contact SDCI for current requirements including size limits, setbacks, owner-occupancy rules, and permitting procedures.

Development Process

Development in Seattle generally requires obtaining the appropriate permits from SDCI. The process typically involves:

1. Zoning Verification — Confirm that your proposed use is permitted in the applicable zoning district
2. Pre-Application Conference — For larger projects, meet with SDCI staff for guidance
3. Design Review — Some projects require design review board approval
4. Building Permit — Apply for a building permit with construction documents
5. Inspections — Schedule required inspections during construction
6. Certificate of Occupancy — Obtain final approval before occupying the structure

For projects that do not conform to existing zoning, property owners may need to seek a variance, special exception, or rezoning through the local board of zoning appeals or planning commission.

Key Considerations

Before starting any development project in Seattle, property owners should:

• Verify the zoning classification of their property
• Review setback, height, and lot coverage requirements for their specific district
• Check for any overlay districts or special regulations
• Determine if the property is in a flood zone using FEMA's flood map service
• Confirm whether HOA covenants or deed restrictions apply
• Contact SDCI at (206) 684-8850 for pre-application guidance

Disclaimer: This guide provides general information about zoning in Seattle and should not be relied upon as legal advice. Zoning codes are subject to change. Always verify current regulations with the City of Seattle SDCI or the municipal code before making development decisions.