New Castle County, DE Environmental Rules: Erosion Control (2026)

Erosion and sediment control in New Castle County operates under the Delaware Sediment and Stormwater Program (7 Del.C. Chapter 40) with plan review and enforcement delegated to the New Castle Conservation District (NCCD) working with NCC Department of Land Use. Any land-disturbing activity exceeding 5,000 square feet requires an approved plan before work begins. Common required BMPs include silt fence along downslope perimeters, stabilized construction entrances of crushed stone or geotextile, inlet protection for catch basins, sediment traps or basins for larger disturbances, erosion control blankets on slopes, and permanent or temporary seeding/mulching for stabilization. Disturbed areas must be stabilized within 14 days (seed) or 7 days (mulch) of cessation of activity under Delaware Standards. Inspections are performed by NCCD or a certified construction reviewer (responsible person) who must be on site for inspections. The Brandywine Creek, Christina River, White Clay Creek, Red Clay Creek, and Chesapeake Bay watershed areas receive heightened scrutiny due to TMDL requirements. Violations often result from failure to install or maintain BMPs, allowing sediment to escape into neighboring properties, storm drains, or streams. DNREC can issue Notices of Violation, Administrative Orders, and civil penalties. Construction site concrete washout, petroleum spills, and uncontrolled concrete pour runoff are common violation triggers.