Accessory Dwelling Units - Are Cities and Counties Doing Enough?

Alexis Biddle
Tue, 05/29/2018 (All day)

On July 7th, 2017 the Oregon Legislature passed SB 1051 with overwhelming bipartisan support.  This legislation requires cities and counties of certain sizes to:

  • Expedite certain categories of affordable housing permits
  • Strengthen requirements for clear and objective review standards for housing developments
  • Streamline local government procedures to make it easier to provide more  housing and especially affordable housing
  • Allow additional accessory dwelling units in single family neighborhoods
  • Allow religious institutions to use their property to develop affordable housing
  • Define “needed housing” as all housing

Within Section 6(5) of SB 1051, cities (with populations over 2,500) and counties (with populations over 15,000) are required to allow at least one accessory dwelling unit (ADU) for each single family dwelling in areas zoned for single-family dwellings inside urban growth boundaries (UGBs). The map and the lists below show where these provisions apply.

Reasonable Siting and Design

Backyard ADU in NE Portland fits seamlessly with the neighborhood. 

An Accessory Dwelling Unit (ADU) is simply a type of housing that offers separate living space on the same lot as another, ‘primary’ home. Because of its relative affordability to build and flexibility in design, the same unit is often used in different ways throughout its life. For example, one can be a permanent rental, a home for a family member, a home office, a short-term rental, and a caretaker’s residence.

The provision of SB 1051 (Section 6(5)) that requires cities to allow accessory dwelling units states the following:

(5)(a) A city with a population greater than 2,500 or a county with a population greater than 15,000 shall allow in areas zoned for detached single-family dwellings the development of at least one accessory dwelling unit for each detached single-family dwelling, subject to reasonable local regulations relating to siting and design.

(b) As used in this subsection, “accessory dwelling unit” means an interior, attached or detached residential structure that is used in connection with or that is accessory to a single-family dwelling.[1]

Many cities have already acted to comply with the law and others are in the process of doing so. As our Urban Advocate, Alexis Biddle, has been reviewing the compliance actions of cities across the state, he’s noted a wide variety of approaches. Some cities are adding ADU provisions out of whole cloth while others are revising existing code provisions that allow, with various regulations, ADUs.  1000 Friends recognizes that each city has its own unique needs, and that there is not a single blanket policy that all cities should adopt to allow for ADUs. However, that doesn’t mean that the intent behind SB 1051 can be subverted through “reasonable siting and design” regulations that effectively limit ADU development.

For instance, some cities have existing, or are proposing, ADU provisions requiring that the owner of the primary dwelling actually reside in one of the dwellings on the lot. Some owner occupancy requirements could respond to needs in some communities where vacation rentals are limiting access to affordable housing. This requirement would serve certain communities while continuing to make it possible to build an ADU on any lot that has a single-family dwelling and is in an area zoned for single-family dwellings.   

In contrast, some proposed and existing regulations do effectively limit the development of ADUs for certain properties with single-family dwellings. Applying minimum lot size regulations to ADUs, for example, has been used in a way that would make it impossible to develop one on a lot that already has a single home on it. This sort of regulation is exactly what SB 1051 intended to avoid. Similarly, requiring an off-street parking place for each ADU could mean that building an ADU is not physically possible on the lot. It can increase the cost to provide the ADU and therefore make it too expensive to build, and it is inconsistent with one of the biggest selling points for ADUs – that you barely notice them. 

Allowing property owners the freedom to develop gentle infill in the form of ADUs is one very needed solution among many more to address our housing crisis. Oregon needs more housing, but it also needs more diverse housing types and in particular, more smaller and affordable housing types to reflect the changing nature of families. The coalition of housing advocates, including 1000 Friends of Oregon, that fought to pass SB 1051 with the explicit purpose of alleviating our extremely strained housing market won broad and bi-partisan support. We will be following the implementation of SB 1051 closely to ensure that local actions are in compliance by the July 1st deadline. You can make a difference in your community by contacting your local planners and elected leaders to encourage codes that realistically allow ADUs in your city and county.

Cities Responsible for Implementing ADU Provisions of SB 1051



Medford Seaside
Ashland Florence Milton-Freewater

Shady Cove

Astoria Forest Grove Milwaukie Sheridan
Aumsville Gladstone Molalla Sherwood
Baker City Grants Pass Monmouth  Silverton
Bandon  Gresham Mount Angel Springfield
Beaverton Happy Valley Myrtle Creek St. Helens
Bend Harrisburg Myrtle Point Stayton
Boardman Hermiston Newberg Sublimity
Brookings Hillsboro Newport Sutherlin
Burns Hood River North Bend Sweet Home
Canby  Hubbard Nyssa Talent
Central Point Independence Oakridge The Dalles
Coos Bay Jacksonville Ontario Tigard
Coquille Jefferson Oregon City Tillamook
Cornelius Junction City Pendleton Toledo
Corvallis Keizer Philomath  Troutdale
Cottage Grove King City Phoenix Tualatin
Creswell Klamath Falls Portland Umatilla
Dallas La Grande Prineville Veneta
Damascus Lafayette Redmond Warrenton
Dayton Lake Oswego Reedsport West Linn
Dundee Lebanon Roesburg Wilsonville
Eagle Point Lincoln City Salem Winston
Estacada Madras City Sandy Wood Village
Eugene McMinnville Scappoose Woodburn City

[1] Section 6, Chapter 745, Oregon Laws 2017. – note: this has been amended by HB4031B to only allow ADUs inside of urban growth boundaries