Lakewood, WA Environmental Rules: Erosion Control (2026)

LMC 12.10.040 requires temporary and permanent erosion and sediment control BMPs on any project that clears, grades or otherwise disturbs a site, designed to prevent, to the maximum extent possible, sediment transport from the project site to downstream drainage facilities, water resources and adjacent properties. LMC 12.11.040(B), Minimum Requirement No. 2 of the City's stormwater code, builds on that duty: every new development and redevelopment project is responsible for preventing erosion and the discharge of sediment or other pollutants leaving the site, and any project meeting the drainage-review thresholds in Table 12.11-1 at LMC 12.11.030 must prepare a construction stormwater pollution prevention plan (SWPPP) as part of its stormwater site plan.

Projects larger than one acre that could discharge to waters of the state, as the City Engineer determines, must also obtain a construction stormwater general permit from the Washington Department of Ecology, with SWPPP guidance available through DOE. LMC 12.11.050 ties the timing to construction sequencing: erosion and sediment control measures for both interim and permanent drainage systems must be built according to the approved plan before any grading or clearing beyond what the erosion control plan itself allows, and they must be maintained until all improvements, restoration and landscaping are complete and the risk of on-site erosion has passed. Recording of short plats and subdivisions cannot occur before drainage facilities, roadways and sidewalks are built and accepted.