Illicit Discharges and Connections
An illicit discharge is defined as any discharge to the storm sewer system that is not composed entirely of stormwater, except for discharges allowed under an NPDES permit or waters used for firefighting operations. An illicit connection is a physical connection to an MS4 that primarily conveys non-stormwater discharges other than uncontaminated groundwater into the MS4.
Illicit discharges and connections allow contaminated wastewater into our local waterways without receiving any treatment. Such activities may be intentional, but also may be unknown to the property owner. For example, a home or business may have a sanitary sewer line connected to the storm system, allowing waste water from toilets and taps to discharge, untreated, into our waterways. Washing a car or cleaning paintbrushes in the driveway or street can send suds and chemicals into the storm drains that connect to rivers and streams. Dumping RV waste or household chemicals directly into a drain is another example of illegal activity that can harm our shared waterways.
Please help us protect the Grand River and other watersheds by reporting illicit discharges and dumping to your local municipality. You may also contact the Michigan Department of Environment, Great Lakes, and Energy's Pollution Emergency Alerting System (PEAS) at 800-292-4706.
To reduce to occurrence of illicit discharges, permitted MS4 communities must develop and implement an Illicit Discharge Elimination Program.
Illicit - Wrong, illegal, needs correction
Discharge - Someone may swim in it
Elimination - Let's get rid of it
Program - Solutions
The ultimate goal of the IDEP is to eliminate all illicit connections and discharges from a municipality's storm sewer system. This is done through dry weather screening and sampling to identify potential illicit discharges, enacting enforceable ordinances, and eliminating connections and problem discharges that are identified. Visit your municipality's website to review their individual IDEP practices.
Dry Weather Flow is noted when it has not rained for at least 72 hours and the storm drain has flow or the drain shows signs of intermittent flow (staining, odor). This may indicate the presence of an illicit discharge.
Sanitary Sewage may be present if there is black staining inside the drainage pipe; visible evidence of sanitary waste, such as toilet paper; or opaque or gray water. Sewage may originate from septic tank overflow pipes or improperly dumped travel trailer waste.
Suds may be harmful to fish because suds deplete oxygen levels in the water. Suds often enter lakes and streams as a result of improperly connected car washes or washing machines.
Oil/Gas is recognized as a sheen on the water. Natural sheens may be differentiated from an oil/gas sheen by swirling the sheen around in the water. If it re-attaches, the sheen is oil/gas. Natural sheens will remain separated. Oil/Gas enters waterbodies via storm water runoff (spills while topping off at gas stations, oil leaks on pavement, etc.) and illegal dumping.
Some images and text borrowed from MDOT's IDEP website. Visit their page for more information and an interactive illicit discharge demonstration.