No. As of October 2026, Oregon law (ORS 197A.425) says the siting and design rules a city applies to ADUs cannot require additional off-street parking, and cannot require the owner to live on the property. Portland states that no extra on-site parking is required for an ADU.
Where does that rule come from?
Oregon's ADU law began as SB 1051 in 2017, which required cities over 2,500 people and counties over 15,000 to allow at least one ADU with each detached single-family house in urban areas. HB 2001 in 2019 added that reasonable siting and design rules may not include owner-occupancy or new off-street parking requirements. The law is now ORS 197A.425.
Is there any exception?
Yes, for vacation rentals. The statute lets a city require owner occupancy or off-street parking for vacation occupancies. That is why short-term rental rules can still carry these conditions.
What if I convert my garage?
The ADU itself cannot trigger a new parking requirement. Some cities have separate standards for the main house, its driveway or alley access; Gresham, for example, has driveway width rules and takes vehicle access from an alley when there is one. We check those for your lot. See garage conversions.
How did local codes respond?
Milwaukie removed its ADU owner-occupancy and off-street parking requirements effective January 1, 2020, saying the change brought its code into line with HB 2001. Portland's ADU zoning summary requires no added parking for an ADU.
Does no parking requirement mean no parking concerns?
It depends on the street. A tenant with a car will park somewhere, and on-street parking is not guaranteed. Keeping a driveway space, or designing around one, can help the unit rent. Those are choices, not legal requirements, under state law.
Related
Sources, as of October 2026: ORS 197A.425; City of Portland ADU zoning summary; City of Milwaukie ADU code amendments page (ZA-2019-002); City of Gresham Development Code Section 10.0110.
Updated October 2026