Whatcom County ADU Planning Guide: Bellingham, Ferndale & Blaine Rules

ADU Regulations: Bellingham vs. Ferndale vs. Blaine

Regulation	Bellingham	Ferndale	Blaine
Max ADUs/Lot	2 (1 ADU + 1 DADU)	1 ADU	1 ADU
Parking	Exempt near transit	1 space required	1 space required
Owner Occupancy	Until 2026	Indefinitely	None
Max Size	1,000 sq ft	800 sq ft	1,000 sq ft

Key Challenges by City

• Ferndale:

  • Urban Growth Areas Only: Rural lots (e.g., near VanderYacht Park) require 5+ acres.

  • Design Review: All ADUs need Planning Commission approval.

• Blaine:

  • Short-Term Rentals: Banned in residential zones.

  • Coastal Rules: ADUs within 200 ft of Drayton Harbor need elevation certificates.

• Lynden:

  • Dutch Village Aesthetics: Sloped roofs and traditional façades often required.

2025–2026 ADU Regulatory Changes

• Statewide Energy Code (Jan 2025): ADUs must meet higher insulation standards (R-30 walls, R-49 roofs), adding ~$8,000 to builds.

• Bellingham Owner Occupancy End (July 2026): Prepare now to rent both units in 2026.

• Whatcom County Climate Plans: Future ADUs may require solar readiness or EV charging.

How to Start Your ADU Journey

1. Lot Analysis: Confirm zoning, setbacks, and utility capacity.

2. Budgeting: Factor in 10–15% contingency for delays or design changes.

3. Permit Strategy: Apply before 2025 to lock in current energy codes.