The bill seeks to enhance affordable and sustainable building practices in Washington State by amending existing regulations and introducing new provisions. It requires cities and counties planning under RCW 36.70A.040 to allow adjustments in building codes, such as permitting retrofits of existing buildings for residential housing to exceed maximum roof heights and setbacks for insulation purposes. Additionally, it mandates similar allowances for new constructions or retrofits that meet passive house requirements. The bill also prohibits local governments from imposing restrictions on housing density, parking requirements, and design standards for affordable residential projects, particularly those utilizing innovative construction methods like modular or mass timber construction.

Moreover, the legislation introduces specific size limits for affordable housing units aimed at low-income and very low-income households, establishing maximum sizes of 400 square feet for studios, 550 square feet for one-bedroom units, 750 square feet for two-bedroom units, and 1,000 square feet for three-bedroom units. It clarifies that co-living housing units are subject to existing provisions and that these size requirements do not apply to low-income housing developed under certain incentive programs. The bill also mandates that cities and counties planning under the Growth Management Act must adopt or amend their development regulations to align with these new requirements within six months of their next comprehensive plan update.

Statutes affected:
Original Bill: 35.21.990, 35A.21.440, 36.70A.620, 19.27.042
Substitute Bill: 35.21.990, 35A.21.440, 36.70A.620, 70.87.030
Second Substitute: 35.21.990, 35A.21.440, 36.70A.620
Bill as Passed Legislature: 35.21.990, 35A.21.440, 36.70A.620
Session Law: 35.21.990, 35A.21.440, 36.70A.620