ADU Permit Requirements in Bothell, WA
ZIP 98012 straddles City of Bothell and unincorporated Snohomish County (Mill Creek / Canyon Park). Bothell itself spans King + Snohomish counties. Inside city limits: Bothell Permit Center. Outside city limits in 98012: Snohomish County PDS. All Bothell applications run through mybuildingpermit.com (regional portal). Electrical permits via WA L&I, not the city. 2021 International Codes effective in Bothell since March 15, 2024.
By Joey, Founder · Last verified May 28, 2026 · How we research →
When you need a ADU permit
WA (covering parts of ZIP 98012), permits are issued by the City of Bothell Permit Center, enforcing the 2021 International Codes adopted by Washington effective March 15, 2024. An accessory dwelling unit (ADU or DADU) requires a full building permit plus trade permits. Washington HB 1337 (effective mid-2024) requires cities to allow ADUs and detached ADUs (DADUs) by-right in most residential zones statewide, capping local design standards. Electrical work goes through WA L&I separately per RCW 19.28. Apply through mybuildingpermit.com.
ADU Permit Costs: Bothell vs. Nearby
| City | Estimated Fee |
|---|---|
| Bothell | N/A |
| Seattle | $750 – $7,500 |
| Spokane | $750 – $7,500 |
| Tacoma | $750 – $7,500 |
Fees shown are estimates based on local building code data. Actual fees may vary based on project scope and valuation. See all Bothell permit costs →
Zoning & HOA Considerations
ADU regulations vary dramatically by state and city. Many states (CA, OR, WA) have preemption laws that override local zoning restrictions. Check both state law and local zoning before designing.
If you live in an HOA community: hOAs have traditionally restricted ADUs, but state preemption laws in CA, OR, WA, and other states now limit HOA authority over ADUs. Check your state's ADU laws, your HOA may not be able to block construction even if CC&Rs appear to prohibit it.
Estimated Project Timeline
Here's a typical timeline for a adu project:
Timeline is based on the typical about 4 weeks permit processing time. Actual timelines vary by project complexity, completeness of application, and current department workload.
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Frequently Asked Questions
Contact the building department for current ADU permit fee information. Fees typically vary based on project scope and valuation.
It depends on the specifics of your project. Some smaller ADU projects may be exempt from permit requirements, while larger ones typically require a permit. Use our free lookup tool to check your specific situation.
Working without a required permit can result in fines, stop-work orders, being required to remove completed work, and complications when selling your home. It's always best to check first.
Typical approval time for ADU permits is about 4 weeks. More complex projects may take longer if plan review is required.
If you live in an HOA community, you may need architectural review approval in addition to a building permit. HOA rules and city building codes are separate, you may need to satisfy both. Review your CC&Rs and submit to your HOA's architectural review committee before starting work.
Learn More About ADU Permits
Read our complete guide covering permit requirements, costs, common exemptions, and the application process.
Read ADU Guide →