Pollutants enter our rivers and streams in a few ways. Most commonly, stormwater runoff picks up pollutants on the landscape and then flows into storm drains that discharge directly into the river. 

Pollutants also enter our water resources from inside homes as water goes down the drainSome of the products we commonly use, like cleaners or pharmaceuticals, shed chemicals and materials that are harmful to water quality and our health. From our homes, these pollutants get into the wastewater but may not be filtered out at treatment plants. The wastewater treatment plants then discharge this water containing these sneaky pollutants into rivers and streams. 

Stormwater runoff graphic

Stormwater runoff picks up pollutants on the landscape and brings them into storm drains. The storm drains discharge into rivers and streams without being treated.

Common Contaminants


The Issue

The rivers in northeastern Illinois are getting saltier and saltier. This is due to increasing use of rock salt in the winter to melt ice on roads, parking lots and sidewalks and to a lesser extent from water softener salt.  


Once chlorides get into the water, they are very difficult and expensive to remove. The best solution is to reduce our chloride use to prevent salt from getting into waterways in the first place. This doesn’t have to come at the cost of safety. We can use the right amount of salt to keep roads and sidewalks safe while also protecting our freshwater resources. Learn more at saltsmart.org  


The Issue

Pesticides, including herbicides that are commonly applied to the suburban and agricultural landscape, are picked up by stormwater and can runoff into local waterways.   


Always follow package instructionsmore is not better. Don’t apply when rain is in the forecast. Avoid application over hard surfaces like sidewalks and driveways and sweep up any excess material. Check out the Conservation@Home program for ideas on a more natural approach to yard care. 


The Issue

An excess of nutrients in bodies of water cause algal blooms, which deplete dissolved oxygen and can kill fish. Learn more about the sources of nutrients and what you can do to help on our Nutrients page. 

Auto Fluids

The Issue

Engine oil, anti-freeze, brake and power steering fluid are very important for our cars but bad for our streams. When these fluids leak from our cars on to roads, parking lots, and driveways they are washed into storm sewers when it rains.


Fix leaks as soon as possible. Use an oil-dry or kitty litter product to absorb leaked fluids and dispose of properly.

Coal Tar Sealants

The Issue

Sealants are applied to asphalt parking lots, driveways, and playgrounds. Coaltar based sealants contain a toxic compound, polycyclic aromatic hydrocarbon (PAH), that is a hazard for aquatic life and human health. Stormwater runoff that flows over surfaces with coal tar sealant picks up PAH and brings it into rivers and streams. Wind, car tires, and shoes also pick up and move PAHs from coal tar sealants.  


Fortunately, there are alternatives to coal tar-based sealants. Asphalt-based sealcoat products have much lower concentrations of PAHs. Residents could also choose concrete or brick driveways that don’t require sealants. Some communities, such as the City of Lockport, have banned the sale, use, and application of coal tar-based sealant products. Many big-box retailers have discontinued the sale of coal-tar based sealants. If you hire someone to seal your driveway or parking lot, ask them what type of product they use. 

More information can be found on the U.S. Geological Survey’s website.

Household Cleaners

The Issue

The increased use of disinfecting products during the pandemic caused a few strains on our wastewater systems. Sanitary and disinfecting wipes do not break down (even if they say they do!). When people flush wipes down the toilet, they can clog pipes (both in your house and beyond), break pumps, and cause backups.  

Also, the process of wastewater treatment uses helpful bacteria to break down human waste so the treated water can be safely discharged into waterways. The increase in anti-bacterial chemicals used for cleaning kill the helpful bacteria we reply on to process waste at treatment facilities.  


Properly dispose of both sanitary and cleaning wipes to maintain our crucial wastewater infrastructure. The only things that should go down your toilet are human waste and toilet paper. The solution to this is easy: throw wipes and paper towels in the trash, not the toilet. 

Use cleaning products according to their labels and dilute cleaners if directed. Use the amount needed to keep your home clean and not more than necessary. Also, avoid any unnecessary flushing of these chemicals down your sink or toilet. Unused cleaners can be properly disposed of according to package instructions or through local household hazardous waste collection sites.

Click here for Will County’s household hazardous waste collection information.

Click here for other household hazardous waste collections in Illinois.

Emerging Contaminants

The Issue

PFAS (Per- and polyfluoroalkyl substances) are a group of manmade chemicals found in food packaging, stain- and water-repellent fabric, nonstick cookware (like Teflon), firefighting foams, and other products. PFAS are accumulating in our bodies and drinking water. In scientific studies, PFAS cause numerous health issues in lab animals. As a new contaminant, the long-term impact to our health is unknown. 

For more information on PFAS, view these EPA and Environmental Working Group resources.  

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