Clean water is our most valuable resource. Join us in our efforts to preserve water quality for future generations! Explore our stormwater interactive to learn useful tips and information on how to prevent stormwater pollution in the Las Vegas Valley!

The Las Vegas Valley is regulated under a joint Municipal Separate Storm Sewer System (MS4) Permit that encompasses five co-permittees: unincorporated Clark County, the cities of Las Vegas, North Las Vegas, Henderson, and the Clark County Regional Flood Control District (CCRFCD). This permit is issued by the Nevada Division of Environmental Protection (NDEP) and regulates urban runoff from the Las Vegas Valley, which discharges into Las Vegas Wash and Lake Mead. The Clark County Water Quality (CCWQ) Stormwater Regulatory Program is responsible for complying with unincorporated Clark County’s obligations to the MS4 Permit. Other MS4 co-permittees have similar programs and CCRFCD coordinates administrative responsibilities for the permit.

Rainfall that does not soak into impervious surfaces, such as paved streets, parking lots, and building rooftops, becomes stormwater runoff and flows into the storm drain system (or MS4). Runoff from streets, curbs and gutters enters storm drains, catch basins, retention basins, channels, and washes pick up deposited and natural pollutants including sediment, trash, chemicals, and pesticides. Storm drains in the Las Vegas Valley convey stormwater runoff into the Las Vegas Wash and ultimately Lake Mead without treatment (beyond some natural uptake at the Clark County Wetlands Park). This is common throughout the country and is a natural part of the water cycle. Pollutants reaching Lake Mead can negatively impact the environment, and the Valley’s primary source of drinking water. The term non-point source (NPS) pollution, or stormwater pollution, is used to describe pollution that cannot be traced to a single source. Cigarette butts, pet waste, and vehicle oils are common examples of NPS pollutants. The Environmental Protection Agency has identified NPS pollution as one of the leading causes of water pollution. The CCWQ Stormwater Regulatory Program was developed to monitor stormwater runoff from construction sites, industrial facilities, and other sites that discharge contaminants throughout unincorporated Clark County, and is regulated under Clark County Code 24.40.