Auburn, WA Environmental Rules: Erosion Control (2026)

Erosion control on Auburn construction sites is governed by ACC Title 15 building and construction code clearing and grading provisions and the Department of Ecology Stormwater Management Manual for Western Washington. Any project that disturbs more than the code threshold of soil, typically 7,000 square feet or small areas on steep slopes in the Lea Hill and West Hill areas, must submit a temporary erosion and sediment control (TESC) plan showing silt fencing, construction entrances, covered stockpiles, inlet protection, and rapid stabilization measures. During the wet season from October 1 through April 30, the amount of exposed soil at any time is further limited, and final stabilization with seed, mulch, or mats is required within short time windows after grading pauses. Sites near the Green River, White River, Mill Creek, and other critical areas have enhanced buffer protection and may require pre-construction meetings and weekly inspections. Discharging muddy water to storm drains or creeks is prohibited under the illicit discharge section of the surface water code and can draw immediate stop-work orders. Homeowners doing minor landscape work generally fall below thresholds, but pool excavations, house demolitions, and larger landscape regrades usually trigger permits. Auburn Public Works (253) 931-3010 can confirm thresholds and review TESC plans.