The Oregon Senate will soon be deciding on a bill that would allow an owner of a lot or parcel at least two acres in size in an area zoned rural residential to build an accessory dwelling unit, or “ADU,” on that lot or parcel, provided there is already a single-family dwelling on the lot or parcel. As such, this bill has the potential of increasing the State’s supply of housing—and potentially affordable housing—in areas where higher densities are not otherwise allowed. Interestingly, a similar bill, SB 88, failed in the 2019 legislative session. 

Rural residential zones exist throughout Oregon but receive relatively little attention from lawmakers. By definition, rural residential zones exist outside of urban growth boundaries but have been excluded, for one reason or another, from the state’s resource land protections. With certain exceptions, those protections typically allow residential uses only in conjunction with a farm or forest use. However, in rural residential zones, a dwelling can be a primary use of the land. Currently, state law allows (but does not require) counties to permit an additional home on a property containing a house built prior to 1945. However, unlike in urban single-family zones, rural residential zones do not have any other by-right accessory dwelling options, making inter-generational, farm help, and affordable housing options in these zones very difficult to achieve. As under current law, SB 391 would allow, but not require, counties to permit accessory dwellings on any rural residential lot regardless of the age of the existing home.

Under SB 391, certain conditions and restrictions would apply to these ADUs; but notably, the bill would require the ADU to be no more than 900 square feet in usable floor area, and would require the ADU to be located no farther than 100 feet from the existing dwelling. SB 391 would also prohibit use of the ADU as a vacation rental, and prohibit subdividing or otherwise dividing the lot or parcel in such a way that would create a separate lot for the ADU. Finally, SB 391 allows for the dwelling and ADU to be considered a single unit for purposes of calculating exemptions from ground water rights requirements. The full text of the bill as of the date of this article can be found here.

The Senate has declared this bill an emergency and as such it will take effect on its passage.

This article summarizes aspects of the law; it does not constitute legal advice. For legal advice for your situation, you should contact an attorney.