Seattle DADU Regulations Guide

Accessory dwelling unit regulations have shifted noticeably with all the zoning changes, permit requirements, and design standards flying around. As someone who has navigated Seattle’s DADU rules extensively, I put in the hours studying building legal units. Today, I will share it all with you.

What DADUs Are

Probably should have led with this issue, to be candid—Detached Accessory Dwelling Units are separate living spaces on single-family lots.

Seattle Requirements

• Size limits based on lot size
• Height restrictions
• Setback requirements
• Owner occupancy rules (check current status)

Permit Process

• Pre-application meeting recommended
• Submit design for review
• Meet building code requirements
• Schedule inspections

Design Considerations

• Utility connections
• Parking requirements
• Privacy for neighbors
• Access and safety