Wash. Rev. Code § 36.70A.680
Accessory dwelling units—Local regulation
Washington · Revised Code of Washington Chapter 36.70A — Growth Management—Planning by Selected Counties and Cities · Status: effective
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- Wash. Rev. Code § 36.70A.680, Accessory dwelling units—Local regulation, Washington, version 1 as recorded 2026-09-28, yourstate.us, https://yourstate.us/provision/1508044
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(1)(a) Cities and counties planning under this chapter must adopt or amend by ordinance, and incorporate into their development regulations, zoning regulations, and other official controls the requirements of this section and of RCW 36.70A.681, to take effect at the same time as the jurisdiction's next periodic comprehensive plan update required under RCW 36.70A.130.
(b) In any city or county that has not adopted or amended ordinances, regulations, or other official controls as required under this section, the requirements of this section and RCW 36.70A.681 supersede, preempt, and invalidate any conflicting local development regulations.
(2) Ordinances, development regulations, and other official controls adopted or amended pursuant to this section and RCW 36.70A.681 must only apply in the portions of towns, cities, and counties that are within urban growth areas designated under this chapter.
(3) Any action taken by a city or county to comply with the requirements of this section or RCW 36.70A.681 is not subject to legal challenge under this chapter or chapter 43.21C RCW.
(4) Nothing in this section or RCW 36.70A.681 requires or authorizes a city or county to authorize the construction of an accessory dwelling unit in a location where development is restricted under other laws, rules, or ordinances as a result of physical proximity to on-site sewage system infrastructure, critical areas, or other unsuitable physical characteristics of a property.
(5) Nothing in this section or in RCW 36.70A.681 prohibits a city or county from:
(a) Restricting the use of accessory dwelling units for short-term rentals;
(b) Applying public health, safety, building code, and environmental permitting requirements to an accessory dwelling unit that would be applicable to the principal unit, including regulations to protect ground and surface waters from on-site wastewater;
(c) Applying generally applicable development regulations to the construction of an accessory unit, except when the application of such regulations would be contrary to this section or to RCW 36.70A.681;
(d) Prohibiting the construction of accessory dwelling units on lots that are not connected to or served by public sewers; or(e) Prohibiting or restricting the construction of accessory dwelling units in residential zones with a density of one dwelling unit per acre or less that are within areas designated as wetlands, fish and wildlife habitats, flood plains, or geologically hazardous areas.