Building an ADU on the Oregon coast presents unique opportunities and challenges. From Wheeler's charming Nehalem Bay setting to Astoria's historic neighborhoods and Seaside's beachfront properties, each coastal community has its own character and regulations.
Coastal Regulations Overview
Wheeler, OR
(Tillamook County)Max Size: Up to 1,200 sq ft
Detached ADUs: 16 ft max height, 4 ft setbacks. County limits: 900 sq ft or 75% of primary home.
Astoria, OR
(Clatsop County)Max Size: Up to 1,200 sq ft
Progressive ADU rules. Similar height and setback requirements. Strong interest in housing density.
Seaside, OR
(Clatsop County)Max Size: Varies
Beachfront properties may face additional tsunami zone and coastal setback requirements.
Special Coastal Considerations
Wildfire Mitigation
Many coastal properties are in high wildfire risk areas. Special building materials and defensible space requirements apply.
Vacation Rental Restrictions
Many coastal counties prohibit ADU use as vacation rentals to preserve housing for residents. Verify local rules before building for this purpose.
Environmental Reviews
Coastal zone construction may trigger stormwater, erosion, and habitat protection reviews. Proximity to wetlands adds complexity.
Utility Capacity
Verify septic system capacity and water supply. Remote coastal lots may need expensive utility upgrades.
Rural Lot Minimums
In unincorporated rural areas, a minimum 2-acre lot is often required for an ADU, and it must be within 100 ft of the primary home.
Coastal Design Tips
Planning a Coastal ADU?
Our team has experience building on the Oregon coast. Get expert guidance for your coastal project.