From white stains on your shoes to blue pockmarks in freshly fallen snow to long lines at the car wash, winter in Chicago means using road salt — a lot of road salt — to keep streets and sidewalks safe.

But research shows road salt doesn’t keep plants, waterways and animals safe. In fact, it actively harms the natural and built environment. So, why can’t Chicago and other snowy cities end their love affair with road salt? It’s complicated, scientists say.

“Once that chloride gets in the water, it doesn’t get out of the water,” said Jennifer Hammer, Vice President of Land and Watershed Programs at The Conservation Foundation. “It’s not like a pollutant that breaks down.”

Here’s what you need to know about how road salt affects the environment and how cities are responding.

How much salt does the city use?

The amount of salt the city uses each year depends on how much snowfall we get. For example, during one of the snowiest winters on record (2013–2014), the city used 370,000 tons of salt on city roads. Chicago has budgeted just under $19 million for road salt since 2022, according to data the city provided.

This follows a larger trend of using more salt during the second half of the 20th century, as the U.S. built up highway systems, says the nonprofit Friends of the Chicago River. Starting in 2018, Illinois officials adopted life water-quality standards, which required cities to work toward significantly reducing their chloride levels. The city of Chicago is working to meet the state standard for chloride in water by 2036.

Why does Chicago still use road salt?

The consensus is this: Road salt is the safest and most cost-effective substance for managing snow and ice.

Chicago gets an average of 3 feet of snow a year, with heavy snowfall years maxing out above 80 inches. And while many cities and researchers have proposed alternatives from salt brine to heated streets, Chicago officials said safety is the “top priority.”

”The #1 objective is to clear roads for First Responders and so people can travel safely,” city officials said in a statement. “We have found that road salt is the most effective for this.”

What alternatives to salt can cities use?

Experts said there isn’t a true alternative to chlorides.

“There are other products that don’t have chlorides in them,” Hammer said. “They’re a lot more expensive, but they have their own environmental impacts. And some of those impacts we may not even fully know yet, because some of them are newer products.”

Hammer said it’s the chloride in salt that does the most harm to plants, water, animals and the built environment. The alternatives below work by reducing the amount of new chloride introduced into the ecosystem.

Erin Allen/WBEZ

You may have heard about the city of Chicago using beet juice on the roads — or maybe you’ve seen city trucks on a bridge before a storm, leaving brown stripes of liquid in their wake. This liquid is called salt brine, and it’s a mixture of road salt, beet juice and water. The city reserves it for bridges and overpasses, which get significantly icy in the winter.

The sugar in beet juice has a lower freezing point than salt and water. That helps lower the freezing point of the brine overall. Also, sugar is sticky when wet, so it helps brine — and any solid road salt added afterward — stick to the road.

When asked why it can’t be used everywhere, the city cited public safety concerns: “We will continue to use the product that is most effective.”

Heated streets

Nearby Holland, Michigan, has a snowmelt system in its downtown area that heats the streets to melt snow and ice before it sticks. It works by taking already-heated water from a nearby power plant and sending it through pipes under the street’s surface. This melts about an inch of snow per hour, at temperatures as low as 15 degrees.

As to whether this could work in Chicago? The size of the downtown area becomes a problem. Holland’s system takes up about 600,000 square feet, compared to 4.2 million square feet here. Hammer said this requires a lot of changes in infrastructure and technology, and Chicago is just not there yet.

Sand

Sand could be an alternative to road salt. But, Hammer said, in urban areas with storm sewers, sand would get washed into the drains and clog the system. It also doesn’t really melt ice — it just provides more traction. Even that is temporary: “While it may start out as a coarse piece of sand,” she said, “once you get 1,520 cars driving over it, now it’s a very small little piece of sand.”

Has any snowy city banned salt?

No — but our neighbors on Mackinac Island in Michigan are famous for being “salt-free.” (Mostly.) They have no use for road salt, mostly because the only automobiles on the whole island are emergency vehicles. They actually try to keep 4 inches of snow on the roads in the winter, so snowmobiles — a common mode of transportation — can get around.

Courtesy of It’s Wonderful Photography

How bad is road salt for pets and other animals?

“There’s all these cascading effects,” said Lauren Salvato, Water Quality Program Leader with the Upper Mississippi River Basin Association. That’s because our environment and the organisms that live there were not designed to handle such salty conditions.

This is especially true for freshwater fish and river animals. Scientists we spoke with said high chloride in our rivers, streams and wetlands can slow their growth and even affect their ability to reproduce, and it can be directly tied to road salt.

In fact, chloride in the Upper Mississippi and the Illinois rivers has risen an average of 35% from 1989 to 2018, according to a study from the UMRBA.

Road salt also changes the soil, so much that it causes dead grass and burnt vegetation. “Before it even gets to our rivers and streams, it’s getting to that soil on the side of the road,” said Hammer.

If you have a dog or an outdoor cat, you may have seen them limping from pain just before or after a heavy snow. That’s because the salt can get stuck in their pads and burn them or dry them out.

As for so-called “pet friendy” road salt, Hammer said that’s not really a thing. “There’s no truth in labeling,” she said. “If you see something that says safe for your pets, there’s nothing out there that we see at the hardware store that’s truly safe for your pets.”

But you can try making your own brine, which would require a significantly smaller amount of road salt. Here’s a DIY salt brine video from Salt Smart, a collaborative committed to road safety and protecting the environment.

Pat Nabong/Sun-Times

What impact does road salt have on drinking water?

To be clear, Chicago’s drinking water is less affected by chlorides from road salt. Our water source is Lake Michigan, which is so vast that any chloride is diluted enough not to be harmful for humans.

But salt is corrosive, and some studies show chloride can cause the release of heavy metals. “When you have high-chloride water coming through your drinking water infrastructure, it’s going to cause the release of any lead that could be in that infrastructure as well,” said Brooke Asleson, Chloride Program Administrator with the Minnesota Pollution Control Agency.

And while Chicagoans may not be at risk, our neighbors down south are affected. “Everything we do in our watershed ends up in the upper basin to the lower basin and down to the mouth of the Gulf,” Salvato said.

Because Chicago waterways are connected to other waterways, it goes beyond just our city and state. Cities and natural areas all along the Mississippi River, as well as the Gulf of Mexico, are seeing some of the same environmental impacts Chicago is dealing with as a result.

Erin Allen is Curious City’s host.