What is Stormwater Runoff
Stormwater runoff occurs when water from rain or snowmelt flows over the ground. Impervious surfaces such as driveways, sidewalks and streets prevent stormwater from naturally soaking into the ground.
Development typically replaces the natural landscape with impervious surfaces like roads, roofs and parking lots. When stormwater cannot sink into the ground, it has nowhere to go but to flow across the surface of the ground.
Why is does it matter?
Stormwater washes pollutants off roads, lawns and other surfaces and carries them into the nearest body of water. These pollutants can harm fish and wildlife populations, kill native vegetation, contaminate drinking water supplies, and make recreational areas unsafe.
What is MS4?
Polluted stormwater runoff is commonly transported through Municipal Separate Storm Sewer Systems (MS4s), from which it is often discharged untreated into local waterbodies. To prevent harmful pollutants from being washed or dumped into an MS4, operators must obtain a National Pollutant Discharge Elimination System (NPDES) permit and develop a stormwater management program.
A Guide to Best Management Practices
REPORT ILLICIT DISCHARGE
Three ways to Report an illicit discharge
If you observe illicit discharges to the storm sewer system, you can report the activity by:
What is an illicit discharge?
Illicit discharges, also known as illegal discharges, are the introduction of non-stormwater runoff, sewage, or hazardous materials into the public stormwater system.
Illicit discharges are:
- Effluent from septic tanks
- Gasoline and automotive fluid spills
- Illegal dumping of household hazardous waste, such as paint
- Improper disposal of auto and household toxins
- Improper disposal of yard waste, such as leaves
- Laundry wastewaters
- Sanitary wastewater
- Sediment and pollutants from construction sites
- Vehicle wash wastewater
With certain conditions, the following are not illicit discharges:
- Dust control water
- Lawn water
- Permitted discharges covered under another permit.
- Street/sidewalk wash water
- Swimming pool discharge
- Water line or hydrant flush water
Illicit discharges are not:
- Air conditioning condensate
- Crawl space pump discharge
- Footing drains
- Foundation drains
- Irrigation water from agricultural sources
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