Residential drafting in Tigard, Oregon
Tigard is postwar ranches, 1970s split levels, and newer infill, mostly wood frame over crawlspaces on relatively flat ground. Compared with West Linn or Oregon City, the sites are more straightforward and the buildings are more predictable.
Split levels are the exception. The floor height changes, stair geometry, and foundation stepping make an attached addition considerably harder than the same work on a ranch, and it is worth establishing early whether the addition attaches or stands separate.
Riparian corridors and floodplain near the Tualatin River affect a meaningful share of the city, and Clean Water Services regulates stormwater across the area. New impervious surface has to be accounted for, which can mean a rain garden or a specific drainage design rather than a note on the plan.
ADU standards
Setback, size, and parking rules for an accessory dwelling unit in Tigard.
| Maximum size, detached | 800 sq ft (TMC 18.220.040(B)) |
|---|---|
| Converting an accessory structure | The 800 sq ft limit applies to the whole combined structure, including any part that stays a garage (TMC 18.220.040(G)) |
| Setbacks | The base zone standard. Rear may reduce to 5 ft at 15 ft tall or less (TMC 18.220.040(D)) |
| Placement | Cannot sit closer to the front property line than the house (TMC 18.220.040(D)(1)) |
| Height, detached | 25 ft (TMC 18.220.040(C)) |
| How many | One detached per lot (TMC 18.220.040(A)) |
| Lot coverage | 80 percent in the RES zones, 90 percent in MUC-1 (Table 18.290.1) |
| Parking | No additional space required (TMC 18.220.010) |
Converting an existing garage carries a rule worth knowing before you draw. The 800 square foot limit applies to the entire combined structure, including whatever part stays a garage (TMC 18.220.040(G)). A 900 square foot garage cannot become a 700 square foot unit with 200 square feet of parking left over.
Tigard also offers a system development charge exemption on city transportation and parks charges for a unit of 1,000 square feet or less, in exchange for a recorded covenant barring short term rental for ten years after final inspection. The exemption sunsets July 31, 2027, and it does not cover county, regional, or utility charges.
Planning office: Tigard Permit Center
Sources: Tigard Municipal Code 18.220, 18.290. Tigard Municipal Code 3.24. ORS 197A.425. Last checked August 2026.
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