*Correction: The original story cited Susan O’Sullivan and it should have stated Mary O’Sullivan. We apologize for this error. 

Today, we are forecasted to experience thunderstorms and have at least one inch of rain. 

But did you know that sometimes the excess rainwater potentially contaminates our drinking water?

This happens because of stormwater runoff. 

According to the Environmental Protection Agency (EPA), stormwater runoff comes from excess rain or snow melting that flows over land or impermeable surfaces like “paved streets, parking lots, and building rooftops, and does not soak into the ground.”

So, where does this excess water go?

The short answer: rivers, lakes, and oceans. 

How does it get there? Sidewalks, sewers, and soil. 

Stormwater runoff enters various waterways through any given slope on the land.

“Even though it [land] looks perfectly flat to your eye, [it] has a gentle slope,” said Biology Professor, Mary O’Sullivan. “That slope always leads down to a waterway, and it could be a lake or a river or the ocean.”

Often before stormwater runoff gets to a waterway, it enters the sewer system. 

“Every street has sewers on it, right?” Sullivan says. 

The sewer system is like an underground transportation system that carries off surface water and other materials within that water into a river or sea. Depending on the type of sewer system, that water and its materials may or may not be sanitized before exiting the sewer system.

Here’s how this works in the Elgin area.

“A storm sewer goes directly to a body of water like the Fox River,” O’Sullivan said. 

A good amount of the water that ends up in the Fox River comes from roadways.

“You have typical things that are on the road, like oils from cars and spills,” explained Nora Bertram, City of Elgin Water Utilities Director. 

According to the EPA, stormwater runoff can pick up oils, chemicals, trash, and other harmful pollutants and take them into groundwater, streams, and other waterways.

When there has been snow, roads typically apply salt, which is a pollutant. 

“Salt is a big one from de-icing operations, so that’s a big concern in the natural waterway,” Bertram says.

Because it contains sodium chloride, an easily absorbed chemical, road salt is a harmful pollutant that erodes soil and dissipates into bodies of water, harming aquatic wildlife and lowering the quality of that body of water.

To tackle this issue, the city uses sensible salting, which is using less salt. 

“By minimizing the amount of road salt we use during icing de-icing operations, [it] prevent[s] an excess of salt running off into our streams,” Bertram said. 

She explained it helps to minimize that runoff.

Not only is road salt found in runoff, but other chemicals in rural and city areas can be found in it as well. 

So, what does the type of area have to do with the chemicals found in the runoff?

The short answer is rural and city areas have different types of chemicals. 

“So in a city, you have lots of industry, right?” O’Sullivan explains. “You have lots of vehicles, and you have lots of homeowners using lots of home chemicals,” O’Sullivan explains.

“And the same thing happens in a rural environment,” she said. “But the difference is in a rural environment, you’re getting agricultural chemicals: fertilizers, pesticides, fungicides, seeds, all kinds of things used on branches and farms.”

However, this problem can be mitigated. 

“A lot of it is public education,” said Bertram. “Things like watching our salt applications in the winter time and trying to educate people about salt and about fertilizers, and how fertilizers are damaging to our natural waterways as well.” 

Bertram also explained there are educational programs for children on this topic, as well as social media campaigns. 

“[A] clean river is a health river,” she said. “It makes for a happier public and a happier environment.”