Oregon HB 2001 went into effect August 8th, 2019, which requires cities with populations greater than 10,000 people to allow duplexes. Previously, some municipalities banned duplexes to be built. The new law will also allow even more density to be established in cities greater than 25,000 people.
READ THE ARTICLE: https://www.sightline.org/2019/06/30/oregon-just-voted-to-legalize-duplexes-on-almost-every-city-lot/