§ 35A.21.440 — New housing in existing buildings—Prohibitions on local regulation.

Washington § 35A.21.440

• Jurisdiction: Washington
• Title 35A: OPTIONAL MUNICIPAL CODE
• Ch. 35A.21: PROVISIONS AFFECTING ALL CODE CITIES

Text

(1)(a) Code cities must adopt or amend by ordinance, and incorporate into their development regulations, zoning regulations, and other official controls the requirements of subsection (2) of this section for buildings in commercial, mixed-use, or residential zones no later than June 30, 2026.

(b) The requirements of subsection (2) of this section apply and take effect in any code city that has not adopted or amended ordinances, regulations, or other official controls as required under this section by the timeline in (a) of this subsection and supersede, preempt, and invalidate any conflicting local development regulations.

(2) Through ordinances, development regulations, zoning regulations, or other official controls as required under subsection (1) of this section, code cities may not:

(a) Impose a restriction on housing unit density that prevents the addition of housing units at a density up to 50 percent more than what is allowed in the underlying zone if constructed entirely within an existing building envelope in a building located within a zone that permits multifamily housing, provided that generally applicable health and safety standards, including but not limited to building code standards and fire and life safety standards, can be met within the building;

(b) Impose parking requirements on the addition of dwelling units or living units added within an existing building, however, cities may require the retention of existing parking that is required to satisfy existing residential parking requirements under local laws and for nonresidential uses that remain after the new units are added;

(c) With the exception of emergency housing and transitional housing uses, impose permitting requirements on the use of an existing building for residential purposes beyond those requirements generally applicable to all residential development within the building's zone, including requiring a change of use permit;

(d) Impose design standard requirements, including setbacks, lot coverage, and floor area ratio requirements, on the use of an existing building for residential purposes beyond those requirements generally applicable to all residential development within the building's zone, except as provided in RCW 36.70A.810 and 36.70A.812 ;

(e) Impose exterior design or architectural requirements on the residential use of an existing building beyond those necessary for health and safety of the use of the interior of the building or to preserve character-defining streetscapes, unless the building is a designated landmark or is within a historic district established through a local preservation ordinance;

(f) Prohibit the addition of housing units in any specific part of a building except ground floor commercial or retail that is along a major pedestrian corridor as defined by the code city, unless the addition of the units would violate applicable building codes or health and safety standards;

(g) Require unchanged portions of an existing building that have been used for residential or previously permit-approved conditioned space purposes to meet the current energy code solely because of the addition of new dwelling units within the building. When any other existing building is converted to new dwelling units, changed portions of each of those new units must meet the requirements of the current energy code, except if:

(i) The square footage of new dwelling units does not exceed 2,500 square feet or 50 percent of the total building square footage, whichever is greater;

(ii) The building owner submits documentation, in a form acceptable to the code city, showing the building's residential units' projected energy use intensity is less than or equal to the energy use intensity target in accordance with the clean buildings performance standard in RCW 19.27A.210 ; or

(iii) In all areas zoned for residential housing, an additional housing unit is created within an existing home;

(h) Deny a building permit application for the addition of housing units within an existing building due to nonconformity regarding parking, height, setbacks, elevator size for gurney transport, or modulation, unless the code city official with decision-making authority makes written findings that the nonconformity is causing a significant detriment to the surrounding area; or

(i) Require a transportation concurrency study under RCW 36.70A.070 or an environmental study under chapter 43.21C RCW based on the addition of residential units within an existing building.

(3) Nothing in this section requires a code city to approve a building permit application for the addition of housing units constructed entirely within an existing building envelope in a building located within a zone that permits multifamily housing in cases in which the building cannot satisfy life safety standards.

(4) For the purpose of this section, "existing building" means a building that received a certificate of occupancy at least three years prior to the permit application to add housing units.

Reviser's note: This section was amended by 2025 c 139 s 4 and by 2025 c 203 s 1, each without reference to the other. Both amendments are incorporated in the publication of this section under RCW 1.12.025 (2). For rule of construction, see RCW 1.12.025 (1).

Legislative History

[2025 c 203 s 1;2025 c 139 s 4;2023 c 285 s 1.]