Washington SB 5184 — Lot Splitting for Housing Capacity (WA)
Tracked preemption from the Washington overlay bundle.
Overview
← All state preemptionsWashington overlay roll-upWashington zoning wikiWashington building codesFederal overlaysGlossaryFederal-conflict: Yes
Effective
2024-07-01
Sunset
—
Authority
state
Scope
state:WA
Other Washington preemptions
Washington HB 1110 — Middle Housing (Tier 1: cities >=75,000)Washington HB 1110 — Middle Housing (Tier 2: cities 25,000-75,000)Washington HB 1110 — Middle Housing (Tier 3: small cities in Tier 1 UGA)Washington SB 5290 — Local Permit Review TimelinesWashington HB 1337 — Accessory Dwelling Units StatewideWashington E2SHB 1220 — Comprehensive Plan Housing ObligationsWashington Growth Management Act — Zoning for Growth Targets
Primary-source summary
SB 5184 — Lot Splitting (2024)Trigger predicate
When this evaluates true for a parcel, the law's preempted fields take precedence over base zoning.
AND
parcel.base_zone_category==res_sfcity.growth_management_act_tierattribute is present
Preempted fields
2 fields on the base district schema are rewritten when the trigger fires.
| Field | Op | Value | Note |
|---|---|---|---|
base_districts[category=res_sf].lot_split_allowed | override | True | Administrative lot splits must be enabled to support HB 1110 middle housing |
review_type | waive_discretionary | — |
Citation
Authority source
WA SB 5184 (2024)
§ RCW 58.17 (amendments)
Research notes
Enables lot splits to support added housing capacity; designed to work alongside HB 1110 middle housing. AICUZ / accident potential zone conflicts flagged via federal_conflict_check for parcels near JBLM or NAS Whidbey.