The Municipal Separate Storm Sewer System (MS4) Permit issued by the Nevada Division of Environmental Protection requires Clark County to regulate industrial and construction sites for stormwater compliance within unincorporated Clark County. As the population of the Las Vegas Valley grows, urban development increases. This means more people, more developed land, and an increase in stormwater runoff. Clark County Water Quality’s Stormwater Inspections mitigate stormwater and non-stormwater discharges from construction projects, industrial facilities and other sites with the potential to discharge contaminates to the Clark County storm sewer system, and are regulated under
Clark County Code 24.40.
The Las Vegas Valley MS4 Permit requires Clark County Water Quality to regulate pollutants in stormwater discharges to public storm systems from the following types of industrial facilities:
- Municipal landfills
- Hazardous waste treatment facilities
- Disposal and recovery facilities, industrial facilities that are subject to section 313 of Title III of the Superfund Amendments and Reauthorization Act of 1986 (SARA), and;
- Industrial facilities that the County determines are contributing a substantial pollutant loading to the public storm sewer system
Clark County Water Quality inspectors look for evidence of process wastewater that has been, or is being, discharged from the facility. In specific, Water Quality inspectors examine:
- Outdoor material and storage areas
- Vehicle and equipment fueling/maintenance areas
- Process management areas, such as loading docks and trash & recycling containers
- Grounds maintenance areas, such as landscape areas and parking lots
- On-site storm drains
The Las Vegas Valley MS4 Permit requires Clark County Water Quality to regulate sediment and other pollutants common in stormwater discharges to public storm drain systems from construction sites. Construction sites that meet any of the following criteria are inspected by Clark County Water Quality:
- Projects that disturb one (1) or more acres, or
- Projects that will disturb less than one (1) acre that are part of a larger development.
Clark County Water Quality inspectors inspect construction sites and evaluate Best Management Practices (BMPs) such as housekeeping measures, perimeter and onsite erosion & sediment control measures, perimeter control measures, chemical storage and pollutant control measures. Specific areas to be inspected include:
- Outdoor material and storage areas
- Vehicle and equipment fueling/maintenance areas
- Process management areas, such as concrete washouts and trash & recycling containers
- Sediment controls
- Discharge points (outfalls)
The Las Vegas Valley MS4 Permit requires Clark County Water Quality to regulate Post-Construction Best Management Practices (BMPs) for new development and significant redevelopment (NDSR) projects, and post-construction projects. Inspection protocols include:
- Verify all temporary construction BMPs such as gravel bags, straw wattles, etc. were properly removed
- Inspect permanent BMPs, and respective their respective location and discharge point
- Review the facility’s Operation and Maintenance Plan to ensure continued compliance with local ordinances
Control measures at each facility must be adequate for preventing the pollutants from leaving the site and must be maintained on an ongoing basis. Inspectors will inspect on-site storm drain systems including drop inlets, drainage swales and channels, as well as the perimeter of the site to determine if an illicit discharge has occurred.
Clark County Code 24.40 authorizes Clark County Water Quality to investigate complaints. Clark County Water Quality investigates illicit discharge complaints at residences, commercial businesses, and construction sites. Please visit the
Illicit Discharge Detection and Elimination page for information on Clark County’s Illicit Discharge Detection and Elimination program.
To report illicit discharges, please complete the Online Violation Form.