wa-law.org > bill > 2025-26 > HB 1010 > Original Bill
The legislature finds that Washingtonians are in a housing crisis and the state needs to produce another 1.1 million homes by 2044 to meet its housing needs. The legislature also finds that accessory dwelling units provide affordable housing, can be built quickly, and can provide supplemental income for property owners. Accessory dwelling units are especially needed in rural communities that do not yet have the infrastructure for larger scale development. Therefore, it is the intent of the legislature to provide pathways for the construction of accessory dwelling units in both urban and rural areas.
A county may authorize development of detached accessory dwelling units in rural areas on lots of any size, even where otherwise prohibited by the county's comprehensive plan, countywide planning policy, or multicounty planning policy, if the detached accessory dwelling units are subject to development regulations that include the following requirements:
A parcel may not have more than one accessory dwelling unit, whether attached or detached.
The detached accessory dwelling unit must be subject to the water supply requirements in RCW 19.27.097 and the following additional requirements:
The detached accessory dwelling unit may not be located on a parcel that uses a water source that is closed to further appropriation.
The detached accessory dwelling unit must use water that is part of the water right for the primary dwelling.
Withdrawals of water by each dwelling unit on the parcel must be metered.
The detached accessory dwelling unit may not be located within, or encroach upon, any existing buffers around critical areas.
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The building permit applicant for the detached accessory dwelling unit must provide documentation demonstrating that the existing or proposed sewage, septic, or on-site sewage system can handle the additional demand placed upon it by the detached accessory dwelling unit.
If the detached accessory dwelling unit will be connected to an existing septic or on-site sewage system, the septic or on-site sewage system must be inspected, prior to issuance of the building permit, by a licensed contractor to ensure that the system is in good working order and capable of handling the increased demand placed upon it by the detached accessory dwelling unit.
The floor area of the detached accessory dwelling unit may not exceed 1,296 square feet, or the square footage that could be authorized by the county as an expansion of the primary dwelling to create an attached accessory dwelling unit, whichever is less. The floor area does not include garages, porches, and unfinished basements.
The detached accessory dwelling unit must be constructed such that exterior materials, roof form, window spacing, and proportions approximate those of the primary dwelling, except if the detached accessory dwelling unit is a mobile home or manufactured home.
The detached accessory dwelling unit must use the same driveway as the primary dwelling.
The detached accessory dwelling unit must be sited to prevent loss of land that is defined as "agricultural land" or "forestland" under this chapter.
Subsection (1) of this section is cumulative to other county authority enumerated in this chapter and does not:
Affect or modify the validity of any county ordinance authorizing accessory dwelling units adopted prior to the effective date of this section;
Exclude other means of authorizing accessory dwelling units in urban or rural areas, if consistent with this section; or
Exclude other innovative techniques under RCW 36.70A.070(5)(b), 36.70A.090, or 36.70A.177, if consistent with this section.
The comprehensive plan, countywide planning policy, or multicounty planning policy for any county that authorizes the development of detached accessory dwelling units in rural areas under subsection (1) of this section must be amended, at its next regularly scheduled update, to allow development of detached accessory dwelling units in rural areas consistent with subsection (1) of this section.
Population growth from the development of detached accessory dwelling units that comply with the requirements of subsection (1) of this section may not be counted for the purpose of determining whether a county is achieving rural or urban growth targets contained in a comprehensive plan, countywide planning policy, or multicounty planning policy.
The definitions in this section apply throughout RCW 36.70A.697, 36.70A.698, 36.70A.680, 36.70A.681, and section 2 of this act unless the context clearly requires otherwise.
"Accessory dwelling unit" means a dwelling unit located on the same lot as a single-family housing unit, duplex, triplex, townhome, or other housing unit.
"Attached accessory dwelling unit" means an accessory dwelling unit located within or attached to a single-family housing unit, duplex, triplex, townhome, or other housing unit.
"City" means any city, code city, and town located in a county planning under RCW 36.70A.040.
"County" means any county planning under RCW 36.70A.040.
"Detached accessory dwelling unit" means an accessory dwelling unit that consists partly or entirely of a building that is separate and detached from a single-family housing unit, duplex, triplex, townhome, or other housing unit and is on the same property.
"Dwelling unit" means a residential living unit that provides complete independent living facilities for one or more persons and that includes permanent provisions for living, sleeping, eating, cooking, and sanitation.
"Gross floor area" means the interior habitable area of a dwelling unit including basements and attics but not including a garage or accessory structure.
"Major transit stop" means:
A stop on a high capacity transportation system funded or expanded under the provisions of chapter 81.104 RCW;
Commuter rail stops;
Stops on rail or fixed guideway systems, including transitways;
Stops on bus rapid transit routes or routes that run on high occupancy vehicle lanes; or
Stops for a bus or other transit mode providing actual fixed route service at intervals of at least fifteen minutes for at least five hours during the peak hours of operation on weekdays.
"Owner" means any person who has at least 50 percent ownership in a property on which an accessory dwelling unit is located.
"Principal unit" means the single-family housing unit, duplex, triplex, townhome, or other housing unit located on the same lot as an accessory dwelling unit.
"Short-term rental" means a lodging use, that is not a hotel or motel or bed and breakfast, in which a dwelling unit, or portion thereof, is offered or provided to a guest by a short-term rental operator for a fee for fewer than 30 consecutive nights.
A county or a city may use a variety of innovative zoning techniques in areas designated as agricultural lands of long-term commercial significance under RCW 36.70A.170. The innovative zoning techniques should be designed to conserve agricultural lands and encourage the agricultural economy. Except as provided in subsection (3) of this section, a county or city should encourage nonagricultural uses to be limited to lands with poor soils or otherwise not suitable for agricultural purposes.
Innovative zoning techniques a county or city may consider include, but are not limited to:
Agricultural zoning, which limits the density of development and restricts or prohibits nonfarm uses of agricultural land and may allow accessory uses, including nonagricultural accessory uses and activities, that support, promote, or sustain agricultural operations and production, as provided in subsection (3) of this section;
Cluster zoning, which allows new development on one portion of the land, leaving the remainder in agricultural or open space uses;
Large lot zoning, which establishes as a minimum lot size the amount of land necessary to achieve a successful farming practice;
Quarter/quarter zoning, which permits one residential dwelling on a one-acre minimum lot for each one-sixteenth of a section of land; and
Sliding scale zoning, which allows the number of lots for single-family residential purposes with a minimum lot size of one acre to increase inversely as the size of the total acreage increases.
Accessory uses allowed under subsection (2)(a) of this section shall comply with the following:
Accessory uses shall be located, designed, and operated so as to not interfere with, and to support the continuation of, the overall agricultural use of the property and neighboring properties, and shall comply with the requirements of this chapter;
Accessory uses may include:
Agricultural accessory uses and activities, including but not limited to the storage, distribution, and marketing of regional agricultural products from one or more producers, agriculturally related experiences, or the production, marketing, and distribution of value-added agricultural products, including support services that facilitate these activities; and
Nonagricultural accessory uses and activities as long as they are consistent with the size, scale, and intensity of the existing agricultural use of the property and the existing buildings on the site. Nonagricultural accessory uses and activities, including new buildings, parking, or supportive uses, shall not be located outside the general area already developed for buildings and residential uses and shall not otherwise convert more than one acre of agricultural land to nonagricultural uses; and
Counties and cities have the authority to limit or exclude accessory uses otherwise authorized in this subsection (3) in areas designated as agricultural lands of long-term commercial significance.
This section shall not be interpreted to limit agricultural production on designated agricultural lands.
This section may not be interpreted to limit the development of detached accessory dwelling units that comply with the requirements of section 2(1) of this act.
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Each comprehensive land use plan and development regulations shall be subject to continuing review and evaluation by the county or city that adopted them. Except as otherwise provided, a county or city shall take legislative action to review and, if needed, revise its comprehensive land use plan and development regulations to ensure the plan and regulations comply with the requirements of this chapter according to the deadlines in subsections (4) and (5) of this section.
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(A) Has a population fewer than 500;
(B) Is not located within 10 miles of a city with a population over 100,000;
(C) Experienced a population growth rate of fewer than 10 percent in the preceding 10 years; and
(D) Has provided the department with notice of its intent to participate in a partial review and revision of its comprehensive plan.
ii. The department shall review the population growth rate for a city or town participating in the partial review and revision of its comprehensive plan process at least three years before the periodic update is due as outlined in subsection (4) of this section and notify cities of their eligibility.
iii. A city or town that opts out of a full review and revision of its comprehensive plan must update its critical areas regulations and its capital facilities element and its transportation element.
c. Except as otherwise provided, a county or city not planning under RCW 36.70A.040 shall take action to review and, if needed, revise its policies and development regulations regarding critical areas and natural resource lands adopted according to this chapter to ensure these policies and regulations comply with the requirements of this chapter according to the deadlines in subsections (4) and (5) of this section. Legislative action means the adoption of a resolution or ordinance following notice and a public hearing indicating at a minimum, a finding that a review and evaluation has occurred and identifying the revisions made, or that a revision was not needed and the reasons therefor.
d. The review and evaluation required by this subsection shall include, but is not limited to, consideration of critical area ordinances and, if planning under RCW 36.70A.040, an analysis of the population allocated to a city or county from the most recent 10-year population forecast by the office of financial management. Population growth from the development of detached accessory dwelling units that comply with the requirements of section 2(1) of this act may not be counted for the purpose of determining whether a county is achieving rural or urban growth targets contained in a comprehensive plan.
e. Any amendment of or revision to a comprehensive land use plan shall conform to this chapter. Any amendment of or revision to development regulations shall be consistent with and implement the comprehensive plan.
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Each county and city shall establish and broadly disseminate to the public a public participation program consistent with RCW 36.70A.035 and 36.70A.140 that identifies procedures and schedules whereby updates, proposed amendments, or revisions of the comprehensive plan are considered by the governing body of the county or city no more frequently than once every year. "Updates" means to review and revise, if needed, according to subsection (1) of this section, and the deadlines in subsections (4) and (5) of this section or in accordance with the provisions of subsection (6) of this section. Amendments may be considered more frequently than once per year under the following circumstances:
The initial adoption of a subarea plan. Subarea plans adopted under this subsection (2)(a)(i) must clarify, supplement, or implement jurisdiction-wide comprehensive plan policies, and may only be adopted if the cumulative impacts of the proposed plan are addressed by appropriate environmental review under chapter 43.21C RCW;
The development of an initial subarea plan for economic development located outside of the 100 year floodplain in a county that has completed a state-funded pilot project that is based on watershed characterization and local habitat assessment;
The adoption or amendment of a shoreline master program under the procedures set forth in chapter 90.58 RCW;
The amendment of the capital facilities element of a comprehensive plan that occurs concurrently with the adoption or amendment of a county or city budget; or
The adoption of comprehensive plan amendments necessary to enact a planned action under RCW 43.21C.440, provided that amendments are considered in accordance with the public participation program established by the county or city under this subsection (2)(a) and all persons who have requested notice of a comprehensive plan update are given notice of the amendments and an opportunity to comment.
Except as otherwise provided in (a) of this subsection, all proposals shall be considered by the governing body concurrently so the cumulative effect of the various proposals can be ascertained. However, after appropriate public participation a county or city may adopt amendments or revisions to its comprehensive plan that conform with this chapter whenever an emergency exists or to resolve an appeal of a comprehensive plan filed with the growth management hearings board or with the court.
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Each county that designates urban growth areas under RCW 36.70A.110 shall review, according to the schedules established in subsections (4) and (5) of this section, its designated urban growth area or areas, patterns of development occurring within the urban growth area or areas, and the densities permitted within both the incorporated and unincorporated portions of each urban growth area. In conjunction with this review by the county, each city located within an urban growth area shall review the densities permitted within its boundaries, and the extent to which the urban growth occurring within the county has located within each city and the unincorporated portions of the urban growth areas.
The county comprehensive plan designating urban growth areas, and the densities permitted in the urban growth areas by the comprehensive plans of the county and each city located within the urban growth areas, shall be revised to accommodate the urban growth projected to occur in the county for the succeeding 20-year period. The review required by this subsection may be combined with the review and evaluation required by RCW 36.70A.215.
If, during the county's review under (a) of this subsection, the county determines revision of the urban growth area is not required to accommodate the urban growth projected to occur in the county for the succeeding 20-year period, but does determine that patterns of development have created pressure in areas that exceed available, developable lands within the urban growth area, the urban growth area or areas may be revised to accommodate identified patterns of development and likely future development pressure for the succeeding 20-year period if the following requirements are met:
The revised urban growth area may not result in an increase in the total surface areas of the urban growth area or areas;
The areas added to the urban growth area are not or have not been designated as agricultural, forest, or mineral resource lands of long-term commercial significance;
Less than 15 percent of the areas added to the urban growth area are critical areas;
The areas added to the urban growth areas are suitable for urban growth;
The transportation element and capital facility plan element have identified the transportation facilities, and public facilities and services needed to serve the urban growth area and the funding to provide the transportation facilities and public facilities and services;
The urban growth area is not larger than needed to accommodate the growth planned for the succeeding 20-year planning period and a reasonable land market supply factor;
The areas removed from the urban growth area do not include urban growth or urban densities; and
The revised urban growth area is contiguous, does not include holes or gaps, and will not increase pressures to urbanize rural or natural resource lands.
Except as otherwise provided in subsections (6) and (8) of this section, counties and cities shall take action to review and, if needed, revise their comprehensive plans and development regulations to ensure the plan and regulations comply with the requirements of this chapter as follows:
On or before June 30, 2015, for King, Pierce, and Snohomish counties and the cities within those counties;
On or before June 30, 2016, for Clallam, Clark, Island, Jefferson, Kitsap, Mason, San Juan, Skagit, Thurston, and Whatcom counties and the cities within those counties;
On or before June 30, 2017, for Benton, Chelan, Cowlitz, Douglas, Kittitas, Lewis, Skamania, Spokane, and Yakima counties and the cities within those counties; and
On or before June 30, 2018, for Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Grays Harbor, Klickitat, Lincoln, Okanogan, Pacific, Pend Oreille, Stevens, Wahkiakum, Walla Walla, and Whitman counties and the cities within those counties.
Except as otherwise provided in subsections (6) and (8) of this section, following the review of comprehensive plans and development regulations required by subsection (4) of this section, counties and cities shall take action to review and, if needed, revise their comprehensive plans and development regulations to ensure the plan and regulations comply with the requirements of this chapter as follows:
Except as provided in subsection (10) of this section, on or before December 31, 2024, with the following review and, if needed, revision on or before June 30, 2034, and then every 10 years thereafter, for King, Kitsap, Pierce, and Snohomish counties and the cities within those counties;
On or before December 31, 2025, with the following review and, if needed, revision on or before June 30, 2035, and then every 10 years thereafter, for Clallam, Clark, Island, Jefferson, Lewis, Mason, San Juan, Skagit, Thurston, and Whatcom counties and the cities within those counties;
On or before June 30, 2026, and every 10 years thereafter, for Benton, Chelan, Cowlitz, Douglas, Franklin, Kittitas, Skamania, Spokane, Walla Walla, and Yakima counties and the cities within those counties; and
On or before June 30, 2027, and every 10 years thereafter, for 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.
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Nothing in this section precludes a county or city from conducting the review and evaluation required by this section before the deadlines established in subsections (4) and (5) of this section. Counties and cities may begin this process early and may be eligible for grants from the department, subject to available funding, if they elect to do so.
A county that is subject to a deadline established in subsection (5)(b) through (d) of this section and meets the following criteria may comply with the requirements of this section at any time within the 24 months following the deadline established in subsection (5) of this section: The county has a population of less than 50,000 and has had its population increase by no more than 17 percent in the 10 years preceding the deadline established in subsection (5) of this section as of that date.
A city that is subject to a deadline established in subsection (5)(b) through (d) of this section and meets the following criteria may comply with the requirements of this section at any time within the 24 months following the deadline established in subsection (5) of this section: The city has a population of no more than 5,000 and has had its population increase by the greater of either no more than 100 persons or no more than 17 percent in the 10 years preceding the deadline established in subsection (5) of this section as of that date.
State agencies are encouraged to provide technical assistance to the counties and cities in the review of critical area ordinances, comprehensive plans, and development regulations.
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The requirements imposed on counties and cities under this section shall be considered "requirements of this chapter" under the terms of RCW 36.70A.040(1). Only those counties and cities that meet the following criteria may receive grants, loans, pledges, or financial guarantees under chapter 43.155 or 70A.135 RCW:
Complying with the deadlines in this section; or
Demonstrating substantial progress towards compliance with the schedules in this section for development regulations that protect critical areas.
A county or city that is fewer than 12 months out of compliance with the schedules in this section for development regulations that protect critical areas is making substantial progress towards compliance. Only those counties and cities in compliance with the schedules in this section may receive preference for grants or loans subject to the provisions of RCW 43.17.250.
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Except as otherwise provided in (c) of this subsection, if a participating watershed is achieving benchmarks and goals for the protection of critical areas functions and values, the county is not required to update development regulations to protect critical areas as they specifically apply to agricultural activities in that watershed.
A county that has made the election under RCW 36.70A.710(1) may only adopt or amend development regulations to protect critical areas as they specifically apply to agricultural activities in a participating watershed if:
A work plan has been approved for that watershed in accordance with RCW 36.70A.725;
The local watershed group for that watershed has requested the county to adopt or amend development regulations as part of a work plan developed under RCW 36.70A.720;
The adoption or amendment of the development regulations is necessary to enable the county to respond to an order of the growth management hearings board or court;
The adoption or amendment of development regulations is necessary to address a threat to human health or safety; or
Three or more years have elapsed since the receipt of funding.
Beginning 10 years from the date of receipt of funding, a county that has made the election under RCW 36.70A.710(1) must review and, if necessary, revise development regulations to protect critical areas as they specifically apply to agricultural activities in a participating watershed in accordance with the review and revision requirements and timeline in subsection (5) of this section. This subsection (8)(c) does not apply to a participating watershed that has determined under RCW 36.70A.720(2)(c)(ii) that the watershed's goals and benchmarks for protection have been met.
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Counties subject to planning deadlines established in subsection (5) of this section that are required or that choose to plan under RCW 36.70A.040 and that meet either criteria of (a)(i) or (ii) of this subsection, and cities with a population of more than 6,000 as of April 1, 2021, within those counties, must provide to the department an implementation progress report detailing the progress they have achieved in implementing their comprehensive plan five years after the review and revision of their comprehensive plan. Once a county meets the criteria in (a)(i) or (ii) of this subsection, the implementation progress report requirements remain in effect thereafter for that county and the cities therein with populations greater than 6,000 as of April 1, 2021, even if the county later no longer meets either or both criteria. A county is subject to the implementation progress report requirement if it meets either of the following criteria on or after April 1, 2021:
The county has a population density of at least 100 people per square mile and a population of at least 200,000; or
The county has a population density of at least 75 people per square mile and an annual growth rate of at least 1.75 percent as determined by the office of financial management.
The department shall adopt guidelines for indicators, measures, milestones, and criteria for use by counties and cities in the implementation progress report that must cover:
The implementation of previously adopted changes to the housing element and any effect those changes have had on housing affordability and availability within the jurisdiction;
Permit processing timelines; and
Progress toward implementing any actions required to achieve reductions to meet greenhouse gas and vehicle miles traveled requirements as provided for in any element of the comprehensive plan under RCW 36.70A.070.
If a city or county required to provide an implementation progress report under this subsection (9) has not implemented any specifically identified regulations, zoning and land use changes, or taken other legislative or administrative action necessary to implement any changes in the most recent periodic update in their comprehensive plan by the due date for the implementation progress report, the city or county must identify the need for such action in the implementation progress report. Cities and counties must adopt a work plan to implement any necessary regulations, zoning and land use changes, or take other legislative or administrative action identified in the implementation progress report and complete all work necessary for implementation within two years of submission of the implementation progress report.
Any county or city that is required by RCW 36.70A.095 to include in its comprehensive plan a climate change and resiliency element and that is also required by subsection (5)(a) of this section to review and, if necessary, revise its comprehensive plan on or before December 31, 2024, must update its transportation element and incorporate a climate change and resiliency element into its comprehensive plan as part of the first implementation progress report required by subsection (9) of this section if funds are appropriated and distributed by December 31, 2027, as required under RCW 36.70A.070(10).
Any county that authorizes the development of detached accessory dwelling units in rural areas under section 2 of this act must revise its comprehensive plan, at its next regularly scheduled update, to allow development of detached accessory dwelling units in rural areas consistent with section 2 of this act.
The legislature recognizes that counties are regional governments within their boundaries, and cities are primary providers of urban governmental services within urban growth areas. For the purposes of this section, a "countywide planning policy" is a written policy statement or statements used solely for establishing a countywide framework from which county and city comprehensive plans are developed and adopted pursuant to this chapter. This framework shall ensure that city and county comprehensive plans are consistent as required in RCW 36.70A.100. Nothing in this section shall be construed to alter the land-use powers of cities.
The legislative authority of a county that plans under RCW 36.70A.040 shall adopt a countywide planning policy in cooperation with the cities located in whole or in part within the county as follows:
No later than 60 calendar days from July 16, 1991, the legislative authority of each county that as of June 1, 1991, was required or chose to plan under RCW 36.70A.040 shall convene a meeting with representatives of each city located within the county for the purpose of establishing a collaborative process that will provide a framework for the adoption of a countywide planning policy. In other counties that are required or choose to plan under RCW 36.70A.040, this meeting shall be convened no later than 60 days after the date the county adopts its resolution of intention or was certified by the office of financial management.
The process and framework for adoption of a countywide planning policy specified in (a) of this subsection shall determine the manner in which the county and the cities agree to all procedures and provisions including but not limited to desired planning policies, deadlines, ratification of final agreements and demonstration thereof, and financing, if any, of all activities associated therewith.
If a county fails for any reason to convene a meeting with representatives of cities as required in (a) of this subsection, the governor may immediately impose any appropriate sanction or sanctions on the county from those specified under RCW 36.70A.340.
If there is no agreement by October 1, 1991, in a county that was required or chose to plan under RCW 36.70A.040 as of June 1, 1991, or if there is no agreement within 120 days of the date the county adopted its resolution of intention or was certified by the office of financial management in any other county that is required or chooses to plan under RCW 36.70A.040, the governor shall first inquire of the jurisdictions as to the reason or reasons for failure to reach an agreement. If the governor deems it appropriate, the governor may immediately request the assistance of the department of commerce to mediate any disputes that preclude agreement. If mediation is unsuccessful in resolving all disputes that will lead to agreement, the governor may impose appropriate sanctions from those specified under RCW 36.70A.340 on the county, city, or cities for failure to reach an agreement as provided in this section. The governor shall specify the reason or reasons for the imposition of any sanction.
No later than July 1, 1992, the legislative authority of each county that was required or chose to plan under RCW 36.70A.040 as of June 1, 1991, or no later than 14 months after the date the county adopted its resolution of intention or was certified by the office of financial management the county legislative authority of any other county that is required or chooses to plan under RCW 36.70A.040, shall adopt a countywide planning policy according to the process provided under this section and that is consistent with the agreement pursuant to (b) of this subsection, and after holding a public hearing or hearings on the proposed countywide planning policy.
A countywide planning policy shall at a minimum, address the following:
Policies to implement RCW 36.70A.110;
Policies for promotion of contiguous and orderly development and provision of urban services to such development;
Policies for siting public capital facilities of a countywide or statewide nature, including transportation facilities of statewide significance as defined in RCW 47.06.140;
Policies for countywide transportation facilities and strategies;
Policies that consider the need for affordable housing, such as housing for all economic segments of the population and parameters for its distribution;
Policies for joint county and city planning within urban growth areas;
Policies for countywide economic development and employment, which must include consideration of the future development of commercial and industrial facilities;
An analysis of the fiscal impact; and
Federal agencies and federally recognized Indian tribes whose reservation or ceded lands lie within the county shall be invited to participate in and cooperate with the countywide planning policy adoption process. Adopted countywide planning policies shall be adhered to by state agencies.
Failure to adopt a countywide planning policy that meets the requirements of this section may result in the imposition of a sanction or sanctions on a county or city within the county, as specified in RCW 36.70A.340. In imposing a sanction or sanctions, the governor shall specify the reasons for failure to adopt a countywide planning policy in order that any imposed sanction or sanctions are fairly and equitably related to the failure to adopt a countywide planning policy.
Cities and the governor may appeal an adopted countywide planning policy to the growth management hearings board within 60 days of the adoption of the countywide planning policy.
Multicounty planning policies shall be adopted by two or more counties, each with a population of 450,000 or more, with contiguous urban areas and may be adopted by other counties, according to the process established under this section or other processes agreed to among the counties and cities within the affected counties throughout the multicounty region.
The countywide planning policy or multicounty planning policy for any county that authorizes the development of detached accessory dwelling units in rural areas under section 2 of this act must be amended, at its next regularly scheduled update, to allow development of detached accessory dwelling units in rural areas consistent with section 2 of this act. Population growth from the development of detached accessory dwelling units that comply with the requirements of section 2(1) of this act may not be counted for the purpose of determining whether a county is achieving rural or urban growth targets contained in a countywide planning policy or multicounty planning policy.