SB 5221
As of January 19, 2021
Title: An act relating to regulation of accessory dwelling units located outside of urban growth areas.
Brief Description: Concerning regulation of accessory dwelling units located outside of urban growth areas.
Sponsors: Senators Gildon, Liias, Darneille, Das, Kuderer, Nguyen, Nobles, Short and Warnick.
Brief History:
Committee Activity: Housing & Local Government: 1/19/21.
Brief Summary of Bill
  • Excludes any new detached accessory dwelling unit (ADU) outside of urban growth areas from inclusion in housing density calculations for that area if the ADU is subject to certain limitations imposed by local development regulations.
Staff: Brandon Popovac (786-7465)

Growth Management Act.  The Growth Management Act (GMA) is the comprehensive land use planning framework for county and city governments in Washington.  Enacted in 1990 and 1991, the GMA establishes numerous planning requirements for counties and cities obligated by mandate or choice to fully plan under the GMA, and a reduced number of directives for all other counties and cities. Twenty-eight of Washington's 39 counties, and the cities within those counties, are planning jurisdictions.
Urban Growth Areas.  Counties that fully plan under the GMA must designate urban growth areas (UGAs), areas within which urban growth must be encouraged and outside of which growth may occur only if it is not urban in nature.  Planning jurisdictions must include within their UGAs sufficient areas and densities to accommodate projected urban growth for the succeeding 20-year period.  In addition, cities must include sufficient areas to accommodate the broad range of needs and uses that will accompany the projected urban growth, including, as appropriate, medical, governmental, institutional, commercial, service, retail, and other nonresidential uses.
Local Planning for Accessory Apartments.  Local governments are required to have accessory apartments, commonly referred to as ADUs, provisions incorporated in their development regulations, zoning regulations, or official controls.  These provisions must be consistent with a 1993 report from the Department of Community, Trade, and Economic Development (CTED) that provided recommendations to the Legislature designed to encourage the development and placement of accessory apartments in areas zoned for single-family residential use.  CTED recommendations include standards and criteria regarding size, parking, design, and quantity of accessory apartments. Local communities have some flexibility to adapt these recommendations to local needs and preferences.  "Local government" means a county planning under the GMA, a city with a population over 20,000, and a county with a population over 125,000.
Accessory Dwelling Unit Regulation.  In 2019, the Legislature encouraged fully planning cities to take an array of specified planning actions to increase residential building capacity.  Specified planning actions include authorizing attached and detached ADUs on all parcels containing single-family homes on lots of a certain size.
In 2020, the Legislature required any city within a county planning under the GMA that has not adopted or substantively amended its ADU regulations within the previous four years to adopt or amend ordinances, regulations, or other official controls that do not require the provision of off-street parking for ADUs within 0.25 mile of a major transit stop, with exceptions.

Summary of Bill:

Any detached ADU located outside of an urban growth area will not be included in the calculation of housing density in that area if the detached ADU is subject to local development regulations that impose the following limitations:

  • a parcel must not have more than one detached ADU;
  • the location, size, and appearance of detached ADUs must be consistent with rural character and not interfere with any agricultural or other natural resource use of the property;
  • detached ADUs must be in close proximity to the primary dwelling unit; and
  • the square footage of a detached ADU may not exceed 50 percent of the square footage of the primary dwelling unit.


The provisions do not apply to any detached ADU in existence before the effective date of the act.

Appropriation: None.
Fiscal Note: Requested on January 16, 2021.
Creates Committee/Commission/Task Force that includes Legislative members: No.
Effective Date: Ninety days after adjournment of session in which bill is passed.
Staff Summary of Public Testimony:

PRO:  The bill provides a tool to add to the housing stock, and a housing option for some who would otherwise require subsidized housing.  It also provides the option for owners to house their families or friends in transition, while still preserving the rural character of the area and neighborhood.  Attached ADUs in these areas are not included in the calculation of housing density.  This bill would treat detached and attached ADUs the same outside of UGA.  There is a fair amount of confusion around detached ADUs as part of housing density, and growth board decisions at the county level.  Rural areas have to be part of the housing inventory solution.  The bill will clarify how and where detached ADUs can be built and how they can be limited.  Smaller ADUs are cost effective and have always been part of the state's rural character.  This bill can help address the state's affordable housing crisis and bring back tools used for generations of families.  Because of a very competitive real estate market, rural areas are in need of additional housing options, like smaller homes.  We need more options across the housing market, both home sales and rental options, in order to provide greater housing inventory.
CON:   The bill will essentially double all zoning regulations across rural areas, and will create larger impacts to water availability and resources.  It might undermine the Hirst settlement agreement.  There will likely be some transportation impacts and potentially a loss in transit service options available to seniors.  The housing shortage within UGAs should be prioritized and explored more to ensure access to health care, schools, and transportation options.  The use of detached ADUs in rural areas should be restricted to family use only.  There are concerns regarding the 50 percent size threshold since the bill would allow a 5000 square foot ADU to be built next to a 10,000 square foot home.

Persons Testifying: PRO: Senator Chris Gildon, Prime Sponsor; Steve Gano, Building Industry Association of Washington; Alisha Harrison, Kitsap and Mason Realtors; Bill Clarke, Washington Realtors; Laura Osiadacz, Kittitas County Commissioner.
CON: Bryce Yadon, Futurewise.
Persons Signed In To Testify But Not Testifying: No one.