Winter Road Salt
by Alaina Engdahl, Rich Fender, Petra Schmalbrock,
February 22, 2026;
Has your car ever looked like this?
After a winter storm, everyone wants our roads and walkways cleared quickly of snow and ice. Road salt helps with that—but too much of a good thing can be a bad thing! Road salt washes into streams and accumulates in ground water. We all know that salt is corrosive and damaging to cars. But did you know how damaging salt is to human health and aquatic life?
Increased Use of Road Salt and Accumulation in Rivers and Groundwater
According to USGS, we now use about 20 million tons of road salt annually, roughly 123 pounds for every American, and use has doubled since 1975. Road salt washes into streams and rivers and accumulates in groundwater.
The Izaak Walton League’s SaltWatch program and various other organizations have demonstrated that chloride levels in surface water increase after road salt application, and that elevated chloride levels persist even during the summer months.
Data from the Miami Conservation District show that the salinity of groundwater is increasing in the Miami Valley aquifer that supplies for the greater Cincinnati area.
Why has the use of road salt doubled since 1975? The population in the USA has increased by 58% from 219 million to 343 million in these past 50 years. But that is only part of the reason. This population growth has led to bigger cities with more and more paved surfaces, such as roads and parking lots. Public expectation is to see bare pavement soon after a winter storm and to drive at all speeds summer or winter. Fear of litigation may be another reason for increased salt use. Last not least is the misconception that more salt removes snow and ice faster. Better knowledge of how deicing works can help reduce the amount of salt we use.
Direct and Indirect Impacts on Human Health
When salt levels rise in streams and groundwater, it can cause real problems for drinking water quality. Road salt impacts drinking water that comes from both private wells and public water treatment plants, which use water from rivers (such as the Scioto) and groundwater. And believe it or not, but many public water treatment plants do not have a good way of removing salt from the water!
When you drink too much water that contains high levels of road salt, it can directly affect human health:
- The most common form of road salt is sodium chloride, which means drinking water severely contaminated with road salt can raise sodium levels in the body. Too much sodium isn’t great for your health — it’s linked to high blood pressure, which can increase the risk of heart disease and stroke. High sodium levels are especially concerning for people with kidney disease or those on dialysis.
- Salt can also wear down household plumbing over time. This is a bigger issue in older homes, where pipes are more likely to be made of copper or lead. The chloride in road salt can speed up a process called galvanic corrosion, which can cause lead to leach from pipes into drinking water. Lead is a heavy metal and is a neurotoxin. It’s particularly dangerous for children and their developing brains—even at incredibly low levels, lead can disrupt brain growth. There are tens of thousands of lead water service lines still in use in central Ohio, so working to minimize road salt in drinking water is extremely important.
Impacts on Aquatic Life
The animals that live in the Scioto River and tributaries are freshwater organisms. They are adapted to living in water with very low salt levels and their bodies constantly adjust the balance of water and salts through a process called osmoregulation. When salt levels in the water rise, water moves out of their bodies and excess salts move in, disrupting this balance. This can cause dehydration, stress, and damage to organs like gills, making it hard for the animals to breathe.
There are two different levels of salt toxicity that we are concerned about:
- Acute salt toxicity is fast and severe. It can occur after winter storms, when melting water quickly washes large amounts of road salt into streams, causing an intense spike in salinity. Acute salt toxicity can rapidly cause freshwater animals to die from organ failure.
- Chronic salt toxicity is slower, but still dangerous. It is the harm caused by the long-term exposure to high salt levels in water. Chronic salt toxicity is considered sublethal—it doesn’t kill instantaneously, but it does sicken freshwater animals and can cause death if conditions last long enough.
Here at SWAG, we are working hard to get a better understanding of how road salt runoff might be impacting Scioto tributaries. Below is a map of some data we collected in January 2026 in the Dry Run stream as it flows through the north Hilltop and Valleyview before merging with the Scioto River. The orange flags met the threshold set by the federal government for chronic salt toxicity. The purple flags are more than double that limit.
Take Action!!!
- Reduce your personal use of road salt! To be best of your ability, physically remove new snow before it compacts into ice. If you need to apply salt, a little goes a long way. 1-2 Tablespoon is recommended per sidewalk square and about 1 cup for the average driveway. You can always add more later! And remember, conventional road salt isn’t going to work hardly at all below 15 °F—so if salt that you have already applied isn’t working, applying more isn’t going to help.
- Contractors and businesses with large parking lots likewise should remove fresh snow first and then apply salt, limiting the use as much as possible. Proprietary road salts, while more expensive, work much more effectively at colder temperatures than conventional road salt and require less material to get the job done.
- Municipalities and ODOT should apply the right amount and type of salt—and in the right way. Brine applicators are now considered best practice, instead of using salt spreaders. The H2Ohio Chloride Reduction Program provides funding for needed equipment and facility upgrades. All of this requires good, advanced knowledge of weather conditions and well-calibrated and maintained equipment.
- All salt must be stored such that it cannot leach into storm sewers and water supplies!
- We need better information about how much salt gets into our waterways. If you would like to help SWAG collect data in the Scioto Watershed using chloride test strips (it’s easy, just dip, wait a few seconds, and read!), please contact us at [email protected].
References
https://ltap.engr.wisc.edu/wp-content/uploads/2019/12/Bltn_006_SaltNSand.pdf
https://www.usgs.gov/media/files/salt-historical-statistics-data-series-140-2017-update
https://www.caryinstitute.org/sites/default/files/downloads/report_road_salt.pdf
https://stroudcenter.org/salt/
https://extension.psu.edu/water-cooler-talk-road-salt-impacts-and-solutions
https://www.mcdwater.org/blog/aquifer/too-much-salt-its-not-good-for-you-or-our-water
