Stop using so much sidewalk salt
Popular Science...
Every winter across most of the northern US, giant bags of salt materialize at grocery stores and home improvement retailers as residents and business owners prepare to combat icy sidewalks and slick driveways. But when it comes to salting walkways and parking lots, most people overdo it, which costs more than just cash; using too much salt can have surprisingly harmful effects on the local environment, water quality, and human health.
The problem with sidewalk salt
When salt is applied to roads and sidewalks as a deicing agent, as snow melts, salt gets washed into streams, lakes, and wetlands. Once there, there’s no practical way to remove it at scale. Fortunately, some municipalities, including the Lake George area in upstate New York, are advocating for more responsible salt usage.
The location offers an excellent case study for how road salt can affect regional waterways and what can be done about it. Since 1980, the Lake George Association (LGA), along with partners like the Waterkeeper Alliance and Jefferson Project, have meticulously studied regional water quality via millions of data points. The Lake George Road Salt Reduction Initiative was created in 2014 after scientists discovered that chloride levels in Lake George tripled over the last 40 years—and road salt was primarily to blame.
LGA tested water quality in not just lakes and creeks, but also in private wells across the watershed. That’s how researchers discovered that over 60 percent of private wells located downslope of state roads exceeded New York State’s drinking water guidance values for sodium thanks to salt-based groundwater contamination. In Mirror Lake and Lake Placid specifically, those concentrations were due in large part to sidewalk and parking lot over-salting.
Over 60 percent of affected wells had salty enough water to be corrosive, making it not only undrinkable but useless for watering plants, unpleasant for bathing, and detrimental to the lifespan of appliances like water heaters, dishwashers and washing machines, explains Brendan Wiltse, president of the Lake George Association.
Homes with older lead pipes fared even worse: Corrosive water can cause the metal pipes to leech lead. In fact, that’s part of what contributed to the drinking water crisis in Flint, Michigan, in 2014, explains Wiltse. These risks are often exacerbated because many homes with wells aren’t regulated or tested like city water systems are, so residents “may not know they’re drinking contaminated water,” he continues.
A spring 2025 report from the New York City Department of Environmental Protection even found that if salt contamination continues increasing as it has for the last 40 years, some watersheds will be above safe maximums by 2108. That means many New York residents won’t have access to potable water.
The environment suffers, too, namely zooplankton that aren’t evolutionarily equipped to handle high salinity in waterways. These creatures act as the basis of the food web—they eat algae, keeping blooms in check, and fish eat them, and so on—so when they suffer, it can cause harmful reverberations up and down the ecosystem, Wiltse says.
The solution to over-salting
The Lake George Association, in partnership with a slew of other environmental organizations, is tackling the problem head on, as are other municipalities around the country. The city is investing in more effective plow blades, high-tech digital data collection, and studies that show using less salt is just as effective, but with less environmental risk.
Brining was adopted, a process of pre-treating roads before a storm with a solution of just 23 percent salt that prevents ice build-up. The organization is also advocating for more cities to adopt their Sustainable Winter Management system (SWiM) to measure salt levels, analyze data, and optimize salt usage for maximum effectiveness without excess.
In upstate New York, it seems to be working. Many municipalities around Adirondack Park are using less salt. Wiltse says Mirror Lake’s salt concentrations are plummeting, thanks to participation of residents and business owners, all while effectively keeping people safe on roads and sidewalks.
Fortunately, reducing salt when it comes to deicing your own sidewalk isn’t complicated. It mostly comes down to quantity.
When, where, and how much salt to apply
How much salt you should use to make any given area safe for pedestrians varies slightly. But the general rule of thumb, according to Wiltse: “One 12-ounce coffee cup of salt is sufficient for a 20-foot driveway or 10 sidewalk squares.”
Avoid what he refers to as the “more-on approach,” which he describes as the practice of continuously sprinkling more on, and on, and on. After all, it only takes a teaspoon of salt to contaminate five gallons of water and make it harmful to aquatic life and undrinkable for humans.
Apply salt to sidewalks, driveways, or parking areas that see regular use, scattering it evenly over the surface. It’s equally important to stay on top of snow removal by shoveling small amounts more frequently, instead of after it’s piled up. Don’t make up for laziness with salt, Wiltse advises. It’s not there to melt six inches of snow away: Cleanup comes first, then salt.
As for when to apply, while most people think of salt as a post-weather treatment, pre-treating walkways is often beneficial. “What salt is best at is preventing the bond of snow and ice onto the surface you’re trying to treat,” Wiltse states. Think of it like oil in a frying pan: You put the oil in your pan before adding your ingredients to prevent them from sticking.
Sprinkle salt before the weather blows in so it forms a liquid brine over the surface. This will prevent snow from bonding to the cement or asphalt, especially when it’s compacted via footsteps or car tires. Doing so will make snow easier to shovel, too.
Salt alternatives: What to use (and not use)
In most cases, regular rock salt (sodium chloride) is more than sufficient. But you may see formulations of calcium chloride and magnesium chloride, too. The latter works more effectively in extra-cold temperatures, but you need less, so use sparsely.
Cat litter or sand is a popular additive, but it’s easier to track indoors, so isn’t a perfect fix for everyone.
Some articles reference more innovative solutions a few municipalities have tried, like beet juice, pickle brine, cheese brine, or beer waste. “The problem with those is they have a lot of sugar in them,” Wiltse says. When they run off into natural bodies of water, bacteria eats the sugar too quickly; the process sucks up excess oxygen in the process, which can kill fish.
So stick with salt, don’t use too much, and sprinkle smart this winter for your own health—and the health of the environment.
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