Lewisville, TX Environmental Rules: Stormwater Management (2026)

Lewisville operates a Phase II municipal separate storm sewer system (MS4) under authorization from the Texas Commission on Environmental Quality (TCEQ). The city's stormwater management program addresses construction site runoff, post-construction stormwater management, illicit discharge detection, and public education. Construction projects that disturb one acre or more of land must obtain a TPDES Construction General Permit (TXR150000) from TCEQ and develop a Stormwater Pollution Prevention Plan (SW3P). The SW3P must address erosion and sediment controls, waste management, and post-construction permanent best management practices. Developers must submit a drainage plan with development applications showing that post-development runoff does not exceed pre-development rates. Detention or retention facilities may be required for projects that increase impervious cover. Illicit discharges to the municipal storm sewer system are prohibited, including wash water, chemicals, oil, grease, and sanitary waste. The city conducts dry-weather screening of outfalls to detect illicit connections. Residents can report illegal dumping or stormwater pollution to Code Enforcement. The stormwater program is administered by the Engineering Department at (972) 219-3590.