Residential drafting in West Linn, Oregon
West Linn is hillside and river country. The housing mixes older homes near the Willamette with large custom construction from the 1990s and 2000s, and daylight basements are common enough to be the first thing worth checking on any addition.
Slope drives the work here. Steep sites, shallow bedrock, and landslide hazard areas mean a geotechnical report is a live question rather than a formality, and excavation costs can decide the project. Retaining walls, access grades, and construction staging are design problems, not site logistics.
The tree canopy is heavy and mature, and trees affect where a building can go before they affect what it looks like.
Because of all that, a basement conversion or a unit above an existing garage is often more workable here than a new detached building on open ground.
ADU standards
Setback, size, and parking rules for an accessory dwelling unit in West Linn.
| Maximum size, attached | 1,000 sq ft (CDC 34.030(A)(2)) |
|---|---|
| Maximum size, detached | 1,000 sq ft or 75 percent of the house, whichever is less (CDC 34.030(A)(2)) |
| Setbacks | The underlying zoning district standard (CDC 34.030(A)(3)) |
| Height, detached | The greater of the house's height or 26 ft (CDC 34.030(A)(4)) |
| How many | One, attached or detached. Not permitted with a duplex, triplex, or quadplex (CDC 34.030(A)) |
| Parking | None required, and no requirement to replace parking lost to a garage conversion (CDC 34.030, CDC 46.090) |
West Linn rewrote its accessory dwelling rules in July 2023 and deleted a great deal. Gone are the required extra parking space, the minimum unit size, the rule placing the unit at least ten feet behind the house, and the requirements to match exterior materials, roof pitch, trim, and windows. If you find guidance describing any of those, it is out of date.
There is also no requirement to replace parking for the house if a garage conversion removes it. The city removed its residential parking minimum entirely in November 2024.
For short term rental, the owner has to live in a dwelling unit on the property (CDC 37.020(A)(8)). The city's own page still says the primary structure, which is narrower than the current code.
Planning office: West Linn Planning Department
Sources: West Linn Community Development Code 34.030. Ordinance 1742, passed July 2023. ORS 197A.425. Last checked August 2026.
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