Clark County, NV Environmental Rules: Stormwater Management (2026)

Clark County is designated a Phase I Municipal Separate Storm Sewer System (MS4) under the federal Clean Water Act. Through its Clark County Code Title 24 and CCRFCD coordination, the county regulates illicit discharges to the storm drain system that drains to the Las Vegas Wash and ultimately Lake Mead. Common prohibited discharges include concrete washout, paint, car wash soap, oil, pesticides, landscape waste, and pool water with chlorine above detection limits. Construction sites disturbing 1 acre or more must obtain a Nevada Division of Environmental Protection (NDEP) Construction Stormwater General Permit and implement a Stormwater Pollution Prevention Plan (SWPPP) with BMPs. In the Mojave Desert, flash flooding during summer monsoon can move massive sediment loads; the CCRFCD manages regional flood channels and detention basins. Post-construction stormwater BMPs are required for new development including retention basins, bioswales, and permeable pavement where feasible. Hydromodification in Las Vegas Wash tributaries is carefully managed to protect downstream Lake Mead water quality.