Key Distinction: Long-Term vs Short-Term Rentals
HB 1337 eliminated owner-occupancy requirements and opened ADUs to long-term rentals. But it specifically does NOT prohibit local restrictions on short-term rentals (stays under 30 days). Cities can still ban or regulate Airbnb/VRBO for ADUs.
If you're considering building an ADU as an Airbnb or vacation rental, the rules depend entirely on your city's short-term rental ordinance — not the state ADU law. Here's what applies in each Whatcom County jurisdiction.
Rules by City
Bellingham
Bellingham has an active short-term rental regulatory framework. Key points:
- Short-term rentals require a city license and must comply with specific operational standards
- Regulations may differ by zone and property type
- Check with Bellingham Planning for the most current STR rules as they apply to ADUs
Contact: Bellingham Planning Dept (360) 778-8300
Blaine
Short-term rentals are banned in residential zones. This includes ADUs. Blaine is explicit about this prohibition even as it launches its "Permit-Ready ADU Program" with pre-approved plans.
If you're building an ADU in Blaine, plan for long-term rental or personal use only.
Lynden
Lynden's ADU regulations are more conservative overall (attached ADUs only in single-family zones, 4.5+ acres for detached). Short-term rental regulations should be verified directly with the city.
Contact: City of Lynden Planning
Ferndale
Ferndale is actively modernizing its ADU regulations with pre-approved designs and streamlined permitting. Check with the city for the most current STR policies as they apply to ADUs.
Unincorporated Whatcom County
County STR regulations may differ from city rules. Properties in unincorporated areas should check with Whatcom County Planning & Development for applicable short-term rental rules.
Contact: Whatcom County PDS (360) 778-5900
Long-Term Rental: Always Allowed
While short-term rental rules vary by city, long-term rentals (30+ day leases) are always allowed for ADUs in all Whatcom County jurisdictions. This is protected by state law.
Long-Term Rental
- Protected by HB 1337
- No owner-occupancy required
- Steady monthly income
- Lower management overhead
Short-Term Rental
- NOT protected by HB 1337
- City-by-city rules
- May require license/permit
- Rules can change
Our Recommendation
Build for long-term rental as your baseline plan. Bellingham's rental market is strong — with WWU students, hospital workers, and a growing tech workforce, demand for quality long-term rentals remains high.
If your city currently allows short-term rentals for ADUs, that's a bonus — but don't build your entire financial plan around STR income that could be regulated away. The most resilient ADU investment is one that works as a long-term rental.
Typical long-term ADU rental income in Bellingham: $1,400-$2,000/month.
Ready to explore your options? Get a free feasibility study to see what's possible on your property, or let our permit team handle the paperwork.
Key Legal Source
HB 1337, Section 2 — explicitly preserves local authority to regulate short-term rentals. View full text.
Last updated: March 2026. Not legal advice. STR regulations change frequently — verify current rules with your local planning department.
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