Road salt, seemingly innocuous, is a silent destroyer of aquatic ecosystems, wildlife, groundwater resources, and transportation infrastructure. It takes just one teaspoon of road salt, which is made of sodium chloride, to pollute five gallons of water.
Road salt is applied to roads, parking lots, and sidewalks to aid in dissolving snow and melting ice for transportation convenience and safety. When snow melts, road salt washes away with it—into storm drains, through stormwater collection system, and ultimately into our waterbodies.
Concentrations of chloride, the primary ingredient in road salt, that exceed 230 milligrams per liter (mg/L) are toxic to aquatic life and plants. Further, salt degrades soils, which disrupts the nutrient balances necessary for plant growth and negatively impacts the microorganisms that foster life in the soil. Just one salt truck containing 24,000 pounds of salt can contaminate more than 65,000 gallons of fresh drinking water and make a half a million gallons of water uninhabitable by fish.
Waterbodies have seen marked increases in chloride concentrations in the past few decades. A 2017 study sampled 7,700 lakes across North America. Researchers found that 20 percent of these lakes had elevated chloride concentrations and lakes closest to roads and parking lots were most likely to suffer. The study predicts that many already-impaired lakes will be too salty to support life within 50 years if salt usage continues at its current rate,.
For example, Lake George, in New York, has experienced a 3.4 percent increase in salt concentrations over the past 30 years. Chloride concentrations have increased in the Mississippi Rive by 85 percent. Even more alarming, chloride concentrations in groundwater rose 521 percent over 30 years in McHenry County, Illinois.
While road salt provides considerable benefits, it also imposes major costs. In the U.S., salt causes an estimated $19.8 to $45 billion in damages to roadways, bridges, vehicles, tourism, and property values every year.
One case in New York demonstrated the extreme costs of salt’s contamination potential. A farmer was awarded more than $91,000 in damages from claiming a trespass onto his property by road salt from the New York State Thruway Authority (NYSTA), which contaminated his surface and groundwater – killing 80 of his cows and corroding his equipment. The court found the NYSTA “maintenance and use of rock salt” constituted “an unlawful invasion of his land” because it elevated chloride levels at the water to a level unfit for consumption.
These issues have sparked action from states, municipalities, transportation departments, and citizen groups. Many entities use alternatives to road salt, such as sugar beet juice, sand, or a salt brine. Salt brine requires just one-third the amount of salt than traditional rock salt with compromise to road safety. Even more effective is physical snow removal—no snow on the road means salt is not needed to melt it away.
Some communities have made strides in reducing road salt, implementing best management practices, training their operators, and investing in technology and alternatives that reduce the demand for road salt. A serious concern for road salt applicators is automobile accident liability, as drivers are conditioned to see streets clear of snow and doused with salt.
The New Hampshire Department of Environmental Services has worked hard to change that. The department introduced the Green SnowPro Program offering “snow and ice management professionals training and certification in state of the art salt reduction practices that prioritize public safety while mitigating salt usage.” Applicators certified by the program obtain liability “protection against damages arising from snow and ice conditions under” New Hampshire state law.
While the New Hampshire program has succeeded, other states, such as Minnesota, have been unable to pass similar “limited liability” legislation. In 2016 and 2017, bills providing limited liability to commercial applicators were introduced by a community group, Stop Over Salting (SOS). The bills made it through several committees but ultimately failed in Minnesota’s 2018 legislative session.
Meanwhile, SOS and other groups continue to fight for legislation to protect waterbodies across the nation.
 Minnesota needs voluntary certification with limited liability for commercial winter maintenance applicators, Stop over Salting (Jan. 2019), https://www.house.leg.state.mn.us/comm/docs/84d5cb7e-cf40-4762-bf3b-78554728465d.pdf.
 Road salt is a problem for rivers. Adding water may be a solution, WBUR (Mar. 2, 2021), https://www.wbur.org/earthwhile/2021/03/02/road-salt-pollution-runoff-brine.
 Road salt reduction, New Hampshire Department of Environmental Services (last visited Apr. 6, 2021), https://www.des.nh.gov/land/roads/road-salt-reduction.
 Ali Hargrove, Why salt is not the solution, The Heights (Mar. 15, 2021), https://www.bcheights.com/2021/03/15/why-salt-is-not-the-solution/.
 Editorial: About all that winter road salt: Can we switch to beet juice?, Chicago Tribune (Mar. 24. 2021), https://www.chicagotribune.com/opinion/editorials/ct-editorial-road-salt-water-vegetation-20210324-dtrkdsqtvbao3jmfmvocq7sqie-story.html.
 Anne Connor, Road salt is imperiling aquatic ecosystems. It doesn’t have to., Undark (Mar. 11, 2021), https://undark.org/2021/03/11/road-salt-imperils-aquatic-ecosystems/.
 Hargrove, supra note 5.
 Stop over Salting, supra note 1.
 Chicago Tribune, supra note 6.
 Peter Mantius, As liability looms for contaminated drinking water, NYS abruptly changes rules for road salt task force, Finger Lakes 1 (Mar. 8, 2021), https://fingerlakes1.com/2021/03/08/as-liability-looms-for-contaminated-drinking-water-nys-abruptly-changes-rules-for-road-salt-task-force/
 Chicago Tribune, supra note 6.
 Connor, supra note 7.
 New Hampshire Department of Environmental Services, Supra note 4.
 Stop over Salting, Supra note 1.