How Tualatin Handles Accessory Structures: A Practical Guide

Tualatin maintains 50 local ordinances across all categories, and 4 of those deal specifically with accessory structures. Here is a breakdown of what the city actually requires, what is prohibited, and where Tualatin falls on the strict-to-permissive spectrum compared to other cities.

Carport Rules

Tualatin Development Code Chapter 40 (Low Density Residential RL Zone) governs carports and other accessory structures. Table 40-3 sets minimum setbacks of 15 feet front, 5 feet side, 15 feet rear, and 20 feet for a garage door, with a maximum structure height of 35 feet and a maximum lot coverage of 45 percent for single-family dwellings. A non-habitable detached accessory structure under 200 square feet and 15 feet tall does not require a building permit but must still meet TDC setbacks.

Key details: Code: TDC Chapter 40 (RL). Side Setback: 5 feet. Rear Setback: 15 feet. Garage Door Setback: 20 feet. Permit Threshold: Over 200 sq ft or 15 ft.

Building a carport in violation of TDC Chapter 40 setback, height, or lot-coverage standards, or installing a structure over 200 square feet or 15 feet tall without a Tualatin Building Division permit, can result in a stop-work order, code-enforcement action, and required removal or after-the-fact permitting. Civil infractions are prosecuted under Tualatin Municipal Code Chapter 7-01 with fines determined by the municipal court, and unpermitted work must be brought into compliance with the Oregon Residential Specialty Code.

Shed Rules

Per Tualatin's Planning FAQ, a non-habitable one-story detached accessory structure like a shed needs no building permit if its floor area does not exceed 200 square feet and it is no higher than 15 feet. Zone setbacks under TDC 40 and 41 still apply.

Key details: Permit Threshold: >200 sq ft OR >15 ft tall. Code Reference: TDC 40, 41; Planning FAQ. RL Side Setback: 5 ft (Table 40-3). RL Rear Setback: 15 ft. Max Lot Coverage: 45% in RL zone.

Sheds over the 200-square-foot or 15-foot threshold without a building permit, or sheds violating the underlying zone setbacks in TDC 40 or 41, are subject to stop-work orders and abatement by Community Development.

If you are coming from a city with tighter rules, you will find Tualatin gives residents more flexibility on shed rules.

ADU Rules

Per TDC 40.220 (RL zone) and TDC 41.220 (RML zone), accessory dwelling units are a permitted housing type subject to TDC 34.600. The city's ADU page confirms three reviews — land use, engineering, and building — are required.

Key details: Code Section: TDC 34.600; 40.220; 41.220. Zone Status: Permitted in RL and RML zones. RL Front Setback: 15 ft (Table 40-3). RL Side/Rear Setback: 5 ft / 15 ft. Reviews Required: Land use + engineering + building.

Building an ADU without TDC 34.600 land use approval or Building Division permits is a code violation. The Building Division can issue stop-work orders. Setback or coverage violations may require removal or modification.

Garage Conversions

Converting a Tualatin garage into living space requires Building Division permits (building, plumbing, mechanical, electrical). If the conversion becomes a separate dwelling unit it must also meet ADU standards under TDC 34.600 and pass land use approval.

Key details: Permits Needed: Building, plumbing, mechanical, electrical. ADU Path: TDC 34.600 if separate dwelling. Land Use Approval: Planning Division. Parking Replacement: Per TDC 73C. Zone Approval: TDC 40.220 / 41.220.

Converting a garage without Building Division permits, or creating an independent dwelling unit without TDC 34.600 approval, is a code violation. The Building Division can issue stop-work orders and require restoration or correction.

The Bottom Line

Tualatin's accessory structures rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Tualatin is broadly strict or permissive.

These rules come from Tualatin's publicly available municipal code. For complete penalty schedules, exemption details, and answers to common questions, see the individual ordinance pages throughout this guide.