House Bill 1110 is currently under review by the Senate. If the Senate passes this bill by majority vote, it will become law in WA state.
Below are key points of the bill as it stands now; subject to amendments by Senators.
Sec. 2. (21) "Middle housing" means buildings that are compatible in scale, form, and character with single-family houses and contain two or more attached, stacked, or clustered homes including duplexes, triplexes, fourplexes, fiveplexes, sixplexes, townhouses, stacked flats, courtyard apartments, and cottage housing.
Sec. 3. [Note: (b) applies to Shoreline as a contiguous urban growth area (UGA) to Seattle]
(1) Except as provided in section 4, 5, or 6 of this act, any city that is required or chooses to plan under RCW 36.70A.040 must provide by ordinance and incorporate into its development regulations, zoning regulations, and other official controls, authorization for the following:
(a) For cities with a population of at least 25,000 but less than 75,000, that are not within a contiguous urban growth area with the largest city in a county with a population of more than 275,000, based on office of financial management population estimates:
(i) The development of at least two units per lot on all lots zoned predominantly for residential use;
(ii) The development of at least four units per lot on all lots zoned predominantly for residential use within one-half mile walking distance of a major transit stop; and
(iii) The development of at least four units per lot on all lots zoned predominantly for residential use if at least one unit is affordable housing.
(b) For cities with a population of at least 75,000, or any city within a contiguous urban growth area with the largest city in a county with a population of more than 275,000, based on office of financial management population estimates:
(i) The development of at least four units per lot on all lots zoned predominantly for residential use;
(ii) The development of at least six units per lot on all lots zoned predominantly for residential use within one-quarter mile walking distance of a major transit stop; and
(iii) The development of at least six units per lot on all lots zoned predominantly for residential use if at least two units are affordable housing.
Sec. 3 (4) A city must allow at least six of the nine types of middle housing to achieve the unit density required in subsection of this section. A city must also allow zero lot line short subdivision where the number of lots created is equal to the unit density required in subsection (1) of this section.
Sec. 3 (5) (c): Except as provided in (a) of this subsection, shall not require through development regulations any standards for middle housing that are more restrictive than those required for detached single-family residences, but may apply any objective development regulations that are required for detached single-family residences, including set-back and tree canopy and retention requirements;