1. (1) Cities and counties planning under RCW 36.70A.040 may not require affordable housing units for low-income or very low-income households, regardless of the unit mix and size of the project, to exceed the following sizes:

   1. (a) 400 square feet for a studio unit;
   2. (b) 550 square feet for a one-bedroom unit;
   3. (c) 750 square feet for a two-bedroom unit; and
   4. (d) 1,000 square feet for a three-bedroom unit.
2. (2) If the average unit size in the project is smaller than the size requirements in this section, the city must allow the affordable housing units to be of a comparable size as the market rate units.
3. (3) Co-living housing units are subject to the provisions of RCW 36.70A.535.
4. (4) This section does not apply to low-income housing developed under an affordable housing incentive program as provided in RCW 36.70A.540.

[ 2025 c 139 s 9.]