Seal of Dane County County of Dane
Dane County Land & Water Resources Department

Report Pollution Entering Storm Drains or Waterways

In Dane County, anything that enters our storm drains eventually makes its way through the storm sewer system to our lakes, rivers, and streams. When debris, trash, chemicals, paint or other substances are placed in our streets, storm drains or drainage ways it is the same as dumping it straight into our waterways. During rain storms only rain should enter the storm drain. If it’s not raining, nothing should be washing down storm drains or into area waters.

If you see illegal discharges or storm sewer dumping, click the button below to fill out an online report. You can also call MDCPH at (608) 266-4821 during business hours. 

To report spills or discharges that require immediate attention during non-business hours (4:00 p.m. - 8:00 a.m.) or weekends (Saturdays and Sundays), please contact the Wisconsin Department of Natural Resources 24-hour Emergency Hotline at 1-800-943-0003.

What is an illegal discharge?

An illegal discharge is any discharge of a potentially polluting substance that reaches a municipal storm sewer, drainage way, wetland, waterbody or groundwater. An illegal discharge can be deliberate, such as an intentional disposal of paint down a storm sewer, or accidental, like with a dumpster. Below, you'll find a list of some types of illegal discharges that are easy to spot. For a more complete list, visit the "What should I report?" tab. 

  • Flowing concrete waste in the gutter, or a stain indicating concrete has entered a storm drain.
  • Wastewater from carpet cleaning. Carpet cleaners are not allowed to discharge any liquid to the gutter, “clean” or otherwise.
  • Discharges of foam are not allowed. Any water containing visible foam in other than trace amounts, should be reported.
  • Liquids leaking out of garbage dumpsters at commercial facilities.
  • Anyone pouring liquid into a gutter or storm drain.
  • Anyone washing painting tools in the gutter, or stains that show this happened.

If you see any of these items being illegally discharged, we ask that you report it using the Report an Illegal Discharge page.

Why does it matter?

When substances are dumped into our storm drains, it travels untreated into the nearest waterway when it rains. Here are a few examples of why this is a problem:

  • Concrete wash water is very alkaline and can change the water chemistry our lakes rivers and streams. This harms aquatic organisms which have adapted to specific water quality conditions. It takes 10,000 gallons of rain water to neutralize just one gallon of concrete waste.
  • Nutrients from dumpster leachate (what leaks out of a dumpster) and carpet cleaning wastewater contain nutrients that act just like fertilizer to support algae growth. This can contribute to more toxic, blue-green algae blooms, which are dangerous to people and deadly to dogs and other animals. When these algae blooms decompose, they consume oxygen in the water and can lead to low oxygen levels. This can suffocate fish and other aquatic organisms.   
  • Discharges of ammonia, degreasers, and other cleansers can discharge from a storm sewer at concentrations that are high enough to kill some organisms outright.
  • Other types of waste can cause long-lasting damage to plant and animal life and their ecosystem.

What should I report?

Some of the most common offenders for illegal discharges are listed below:

  • Concrete Waste: Wastewater from concrete truck chutes, water used for tool clean up, or dried residue in the gutter.
  • Waste Water: Water that was dumped into the gutter or down a storm drain from things like mopping and carpet cleaning.
  • Used Cooking Oil: Spills from tipped over storage drums and containers filled beyond capacity.
  • Automotive Fluids: Illegal discharges of motor oil or antifreeze. Vehicles that are leaking fluid.
  • Paint: Wet paint or water from tool/brush clean up dumped in the storm sewer.
  • Leachate: Rain that ran through a full dumpster, or liquids dumped in the trash leaking onto pavement.
  • Sediment: Pit dewatering (pulling water out of construction excavation area) without proper filtration.
  • Solid Waste: Mulch, soil, garbage, deposited in the street/gutter, or improperly stored waste.
  • Restaurant Hood Cleaning Waste: Discharges of cleansers or grease washed off restaurant ventilation equipment.
  • Pressure Washing Wastewater: Discharges from outside washing when the wastewater flows to the storm sewer.???

What happens after I report?

We work with the local municipality or Public Health Madison & Dane County to investigate discharges and stains that show waste was dumped on streets or in gutters and storm sewers to:

  • Find out what was discharged and who discharged it,
  • Determine if there is a threat to people or the environment, and
  • Make sure the problem is corrected.

If we are able to determine who was involved in the illegal discharge, we will typically follow up with the individual or company involved using the following methods. 

  • For an individual: In general, we focus on providing education if a person is acting alone. This means we tell them how to dispose of waste properly and how illegal discharges hurt our environment. If someone has repeated violations or it is a major offense, we refer the complaint to the city or county lawyers for legal action.
  • For a business: We handle complaints about businesses differently because there is a greater potential for repeat violations. We send certain types of businesses with a higher probability of violations (carpet cleaners, pressure washers, restaurant vent cleaners, concrete contractors, lawn care businesses) an annual letter describing best management practices for disposing of waste and the consequences of not following these practices. Because we give ample warning and education, we consider these violations deliberate actions and issue a ticket or, in exceptional cases, refer them to city or county lawyers for legal action.

Illegal (Illicit) Discharge Ordinance

To prevent water pollution from threatening our waters, Dane County passed an illicit discharge ordinance in 2021. This ordinance prohibits illicit discharges and aims to prevent and eliminate illegal discharges. The ordinance also gives Dane County enforcement authority.


Everyday Actions You Can Take to Protect Our Waters