Do I need a adu permit in Seattle?

Yes. Seattle requires a adu permit for this type of project. Submitting without a permit may result in fines, required removal, or complications when selling your property.

How long does adu permit approval take in Seattle?

Processing times in Seattle vary depending on project complexity and current review volume. The process involves 7 steps. Contact Seattle Development Services for current timelines.

What documents are required for a adu permit in Seattle?

Seattle requires 6 documents including Master Application and Permit, Architectural Plans, Site Plan, Structural Plans and Calculations, and others. See the full list above for details.

What happens if I build without a adu permit in Seattle?

Building without a permit in Seattle can result in stop-work orders, fines, required removal of work, difficulty selling your property, and insurance complications. It is strongly recommended to obtain proper permits before starting work.

Can PermitMagic help prepare my adu permit submission in Seattle?

Yes. PermitMagic generates a submission-ready packet tailored to Seattle's requirements, including a document checklist, workflow steps, and authority references. Start a permit plan to get your personalized packet.

How much does a adu permit cost in Seattle?

ADU permit fees in Seattle typically range from $7,500 to $24,750, depending on project scope. Fees may include building permit, plan review, and technology surcharges. Verify current fees with Seattle.

ADU Permit Online Portal Guide in Seattle, Washington

Everything you need to apply for a adu permit in Seattle, Washington — documents, fees, steps, and a downloadable submission packet.

Build My Permit Packet View Requirements

Key Facts

Permit required: Yes
Submission method: Online
Typical fee range: $7,500 – $24,750
Review time: Varies by jurisdiction
Inspections: 6 inspections required

VerifiedLast verified: Feb 15, 20262 verified sources

Seattle SDCI

Verified

7-step online submission process — account registration required[1][2]

Open Portal

Step 1: Pre-Design Review

[3][4]

Attend neighborhood consultation meeting and verify zoning compatibility for ADU/DADU

Portal steps may change without notice. Always confirm the current process at Seattle's online portal.

Generate your permit packet

Get a personalized ADU permit packet for Seattle, Washington — tailored to your project details.

Required forms: Master Application and Permit, and more
Pre-filled templates: Permit Cover Sheet
Fee breakdown: $2,500–$15,000 estimated total
Step-by-step Seattle SDCI portal submission guide
Inspection prep checklist (6 items)
Personalized for your specific project details

Build My Permit Packet

Free to preview · Pro to download

Required Documents

Seattle requires the following documents for this permit application.

Master Application and Permit

Completed Seattle Master Application (Master Use Permit) for ADU/DADU projects

Architectural Plans

Architectural drawings prepared by Washington licensed architect including floor plans, elevations, sections, and building details

Site Plan

Site plan showing lot boundaries, setbacks, building location, parking, open space, and access ways

Structural Plans and Calculations

Structural design sealed by Washington licensed structural engineer

Utility System Plans

Utility connection plans for water, sewer, electric, gas, and separate metering details

Geotechnical Report (if required)

Geotechnical investigation report if site conditions warrant or foundation type requires

Fees and Timeline

Fee Breakdown

Fee	Range	Confidence
ADU Permit Fee	$5,000 – $15,000	Verified
Plan Review Fee	$2,500 – $9,750	Verified

Inspections Required

Foundation and footing inspection

Framing inspection with structural verification

Electrical installation and panel inspection

Plumbing rough-in and fixture inspection

Mechanical system and HVAC inspection

Final inspection and Certificate of Occupancy

Authority Sources

Data on this page is sourced from official records published by the permitting authority. Always verify requirements directly before submitting.

Seattle SDCI

Last verified: February 15, 2026

2 sources referenced

Official page

Seattle Municipal Code Title 23 (Land Use Code)

Verified February 15, 2026

Portal guide

Seattle SDCI Permit Portal

Verified February 15, 2026

Official page

SDCI ADU and DADU Design Guide

Verified February 15, 2026

Frequently Asked Questions

Do I need a adu permit in Seattle?: Yes. Seattle requires a adu permit for this type of project. Submitting without a permit may result in fines, required removal, or complications when selling your property.
How long does adu permit approval take in Seattle?: Processing times in Seattle vary depending on project complexity and current review volume. The process involves 7 steps. Contact Seattle Development Services for current timelines.
What documents are required for a adu permit in Seattle?: Seattle requires 6 documents including Master Application and Permit, Architectural Plans, Site Plan, Structural Plans and Calculations, and others. See the full list above for details.
What happens if I build without a adu permit in Seattle?: Building without a permit in Seattle can result in stop-work orders, fines, required removal of work, difficulty selling your property, and insurance complications. It is strongly recommended to obtain proper permits before starting work.
Can PermitMagic help prepare my adu permit submission in Seattle?: Yes. PermitMagic generates a submission-ready packet tailored to Seattle's requirements, including a document checklist, workflow steps, and authority references. Start a permit plan to get your personalized packet.
How much does a adu permit cost in Seattle?: ADU permit fees in Seattle typically range from $7,500 to $24,750, depending on project scope. Fees may include building permit, plan review, and technology surcharges. Verify current fees with Seattle.