4\u20136 weeks
Typical Type I timeline
Type I
Standard ADU permit process
(360) 778-8300
Bellingham Planning
Which Permit Type Do You Need?
Type I — Administrative Review (Most ADU Projects)
The standard and fastest path for ADU permits. Can be submitted concurrently with your building permit application. No neighbor notification required. Learn more about Bellingham's ADU ordinance (BMC 20.10.036).
Use for: Standard ADUs under 1,000 sq ft
Type II — Enhanced Review
Required only for projects resulting in 7+ total dwelling units (including ADUs) under the Interim Middle Housing Ordinance 2025-12-032. Requires a 500-foot mailing list notice.
Use for: Large multi-unit projects (rare for standard ADU builds)
Conditional Use Permit (CUP)
Required for oversized detached ADUs exceeding 1,000 sq ft. Involves a public hearing before the Hearing Examiner, 500-foot mailing list, and neighborhood representative notification. Significantly longer timeline.
Use for: D-ADUs over 1,000 sq ft only
Type I Permit Process: Step by Step
Pre-Application Research
1–2 weeks- Verify zoning district and ADU eligibility for your parcel
- Check for critical areas, watershed overlay, and setback requirements
- Determine utility capacity (sewer/water connections)
- Review lot coverage and open space requirements
Pro tip: Our free feasibility study handles all of this automatically. Or schedule a pre-application meeting with Bellingham Planning. Start with your free report.
Design & Documentation
2–4 weeks- Hire an architect or use pre-approved ADU plans
- Prepare site plan showing ADU placement, setbacks, and access
- Create floor plans and elevations
- Prepare drainage/stormwater plan
- Complete energy code calculations (WA Energy Code)
- Get a boundary/site survey if needed
Pro tip: Working with a designer experienced in Bellingham ADUs saves time. They know what the city wants to see.
Submit Application
1 day- Complete land use application form
- Submit building permit application (can be concurrent with Type I)
- Include all required drawings and documentation
- Pay application fees
Pro tip: Submit a complete package the first time. Incomplete applications are the #1 cause of delays.
City Review
2–4 weeks- Planning department reviews for zoning compliance
- Building department reviews structural, electrical, plumbing plans
- Fire department reviews access and safety
- May receive correction letters — respond promptly
Pro tip: Stay responsive. When the city sends corrections, address them within days, not weeks.
Permit Issued
—- Building permit issued — construction can begin
- Post permit on-site as required
- Schedule required inspections as construction progresses
- Final inspection for Certificate of Occupancy
Pro tip: Your contractor should be familiar with the Bellingham inspection schedule. We coordinate all inspections as part of our build process.
Before you start the permit process: Get a free feasibility study to confirm your property's zoning, setbacks, and critical areas. This saves you from investing in design work for a property that may not qualify. Already know you qualify? See our full cost breakdown to budget the complete project.
Required Documents Checklist
Tips for Faster Approval
Schedule a pre-application meeting with planning staff — it's free and saves weeks of back-and-forth.
Use an architect or designer who has done Bellingham ADU projects before. They know the reviewers' expectations.
Submit during off-peak months (January–March) when the planning department is less busy.
Respond to correction letters within 3 business days to keep your application at the top of the queue.
Consider our $1,500 permit package — Loren has relationships with the planning department and knows exactly what they need. See our full process.
Bellingham Planning Department
Phone: (360) 778-8300
Email: [email protected]
ADU page: cob.org
Municipal code: BMC 20.10.036
Last updated: March 2026. Not legal advice. Verify current requirements with Bellingham Planning.
Let Us Handle the Permitting
Our $1,500 permit package covers all zoning verification, documentation, and city coordination.
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