King County's Critical Areas Ordinance Update: What to Expect

King County is in the final stretch of updating its Critical Areas Ordinance (CAO), with adoption expected by December 2025. The CAO governs protections for environmentally sensitive areas—like wetlands, streams, aquifers, geological hazard areas and conservation areas—and this update will directly impact site planning for developments that include or are near such areas.

The proposed changes to the CAO were submitted to the County Council as Proposed Ordinance 2024-0408. The Key updates include expanded buffer requirements, additional permitting procedures, and stronger mitigation standards. As King County moves toward final adoption of the updated Critical Areas Ordinance, developers should stay closely tuned. With stricter protection measures for critical areas on the horizon, it will be helpful to remain informed about evolving regulations that may affect project feasibility.

Please contact DWT's land use team with questions regarding the potential impacts of this upcoming change to King County's land use regulations.