Substitute House Bill 1160 (H-1101.3) amends existing Washington planning laws (RCW 36.70B.020, 36.70A.030, 36.70A.630, and 36.70A.635) to change definitions, limit how local design review may be applied, and impose new procedural and regulatory requirements on cities and counties. The bill clarifies and adds definitions (for example: closed record appeal, open record hearing, public meeting, administrative design review, and various household income categories), requires administrative design review to be based solely on clear, objective, and ascertainable design and development standards and generally without a public predecision hearing except where state or federal law or local historic designation requires additional review, and requires any design review to be conducted concurrently or logically integrated with the consolidated project permit review process in RCW 36.70B.120(3). It also prohibits a local government from requiring more than one architectural drawing set of one design concept as a prerequisite to review of a housing development permit application. The bill makes substantive land use and zoning changes by requiring cities that plan under RCW 36.70A.040 to adopt minimum unit-per-lot development levels by ordinance tied to city population thresholds (specific unit minimums vary by population and proximity to major transit stops), to allow specific types of middle housing and accessory units, and to treat middle housing under the same permit and environmental review rules as detached single-family residences except as state law requires otherwise. It creates affordability-linked options for additional units (requiring affordable units to be maintained for at least 50 years with a recorded covenant or deed restriction), sets limits on required off-street parking for middle housing (including no off-street parking required within one-half mile of a major transit stop and per-unit caps tied to lot size), and lists narrow exceptions to those parking limits based on certified empirical studies or proximity to very large airports. The changes also include specified exemptions for lots in or near critical areas, certain aquifer and watershed protections, urban separators, and other narrowly defined areas. The bill also adjusts timelines and planning obligations: a complying city that has not received a timeline extension under RCW 36.70A.638 need not update its capital facilities plan element to accommodate the increased housing required by chapter 332, Laws of 2023 until its first periodic comprehensive plan update on or after June 30, 2034, and until June 30, 2026 certain additional residential capacity on lots with critical areas or buffers may not be treated as inconsistent with countywide or multicounty planning policies or growth targets under RCW 36.70A.210. These are regulatory and procedural changes to land use and permitting processes rather than creation of crimes or penalty changes. Several important details are incomplete or unclear in the extracted text: the green space definition is truncated; the amendment to RCW 36.70A.630 ends mid-sentence and the identity of "the department" that must certify certain empirical studies is not specified; the list of the nine types of middle housing referenced is not included; and some edits to the public meeting definition show markup that is not fully explained. The summary is limited to the provisions present in the extracted facts.

If enacted, the bill will make local design review more administrative and predictable and require many cities to allow more housing units per lot. Planning directors can approve design through clear, objective standards without a public predecision hearing in most cases, cities may not demand more than one architectural drawing set to start review, and design review must be integrated with consolidated permit review. Cities over specified population thresholds will have to authorize minimum unit-per-lot levels (higher near major transit stops and for developments that include affordable units), allow many types of middle housing and certain short subdivisions, and follow new parking limits near transit; developers who commit to long-term affordability can qualify for additional units if they record 50-year covenants. The people and organizations most affected are city planning departments, city councils, and housing developers. Cities will need to change development regulations, zoning codes, and permitting practices to meet the unit and parking rules and to track affordability covenants, but they get a delayed need to update capital facilities plans until the first periodic comprehensive plan update on or after June 30, 2034, which reduces near-term planning and funding pressure. Developers will have more options to build denser housing and potentially gain extra units by providing long-term affordable housing, though they and cities will take on administrative costs and obligations to record and enforce 50-year affordability restrictions. Some important implementation details and certain cross-references (including a few cut-off provisions and which state department handles certain certifications) are not fully clear from the excerpt.