Growth Management Act. The Growth Management Act (GMA) is the comprehensive land use planning framework for counties and cities in Washington. The GMA establishes land use designation and environmental protection requirements for all Washington counties and cities. The GMA also establishes a significantly wider array of planning duties for 28 counties, and the cities within those counties, that are obligated to satisfy all planning requirements of the GMA.

The GMA directs fully planning jurisdictions to adopt internally consistent comprehensive land use plans. Comprehensive plans are implemented through locally adopted development regulations, and both the plans and the local regulations are subject to review and revision requirements prescribed in the GMA.

Comprehensive Plan Updates. Counties and cities are required to review and, if necessary, revise their comprehensive plans and development regulations every ten years.

The ten-year review and revision deadlines are staggered for different counties. For King, Kitsap, Pierce, and Snohomish counties, and the cities within those counties, the deadline was December 31, 2024. Clallam, Clark, Island, Jefferson, Lewis, Mason, San Juan, Skagit, Thurston, and Whatcom counties, and the cities within those counties, have a deadline of December 31, 2025. Benton, Chelan, Cowlitz, Douglas, Franklin, Kittitas, Skamania, Spokane, Walla Walla, and Yakima counties, and the cities within those counties, have a deadline of June 30, 2026. Adams, Asotin, Columbia, Ferry, Garfield, Grant, Grays Harbor, Klickitat, Lincoln, Okanogan, Pacific, Pend Oreille, Stevens, Wahkiakum, and Whitman counties, and the cities within those counties, have a deadline of June 30, 2027.

In 2022 and 2024, the Legislature temporarily amended the deadline to review and, if necessary, revise the comprehensive plans of King, Kitsap, Pierce, and Snohomish counties, and the cities within those counties, and Clallam, Clark, Island, Jefferson, Lewis, Mason, San Juan, Skagit, Thurston, and Whatcom counties, and the cities within those counties. These counties are required to review and revise their comprehensive plans and development regulations no later than December 31, 2024, and December 31, 2025, respectively. Following the 2024 and 2025 review cycles, these counties return to the regularly scheduled ten-year review dates.

Beginning six months after its next periodic comprehensive plan update, a fully planning county or city must ensure local development regulations apply only clear and objective design review standards to the exterior of new development, except for certain designated landmarks and historic districts.

No later than six months after its next required comprehensive plan update, fully planning cities meeting population requirements must allow for the development of a minimum number of units on all residential lots, unless zoning permitting higher densities or intensities applies, as follows:

• cities with a population of at least 75,000 must include authorization for at least four units per lot; six units per lot if at least two of the units are affordable housing; and six units per lot within one-quarter mile walking distance of a major transit stop;
• cities with a population of at least 25,000 but less than 75,000 must include authorization for at least two units per lot; four units per lot if at least one unit is affordable housing; and four units per lot within one-quarter mile walking distance of a major transit stop; and
• cities with a population less than 25,000, within a contiguous urban growth area (UGA) with the largest city in a county with a population of more than 275,000, must include authorization for the development of at least two units per lot.

Beginning six months after its next periodic comprehensive plan update, a fully planning city or county must ensure local development regulations allow for the construction of accessory dwelling units (ADUs) within UGAs and comply with certain policies related to siting and permitting of ADUs.

Benton, Chelan, Cowlitz, Douglas, Franklin, Kittitas, Skamania, Spokane, Walla Walla, and Yakima counties, and the cities within those counties are required to review and revise their comprehensive plans and development regulations no later than December 31, 2026. Following the extension provided for the 2025 review cycle, these jurisdictions will resume the regularly scheduled ten-year review cycle on June 30, 2036.

Counties and cities planning under the GMA must apply only clear and objective design review standards to the exterior of new development, except for certain designated landmarks and historic districts, at the same time as the jurisdiction’s next periodic comprehensive plan update, rather than six months after their update.

Certain cities planning under the GMA must authorize minimum development densities in residential zones and include specific provisions related to middle housing in their development regulations by the city’s next periodic comprehensive plan update, rather than six months after the city’s update.

Counties and cities planning under the GMA must ensure that local development regulations allow for the construction of ADUs within urban growth areas at the same time as the jurisdiction’s next periodic comprehensive plan update, rather than six months after their update.