Hidden Costs of Oversalting
Once salt is in the environment it doesn’t go away. It ends up in our lakes, rivers, streams and wetlands, putting aquatic life at risk and endangering our freshwater resources. Our local lakes, waterways, groundwater and soil have been absorbing virtually all of the salt spread in the city for more than six decades. Chloride from salt is toxic to aquatic life and degrades the natural ecosystem of our lakes. It only takes 1 teaspoon of salt to pollute 5 gallons of water to a level that is toxic to freshwater ecosystems.
Salt is showing up at alarming levels in local lakes and groundwater. Lake Wingra’s chloride concentration has increased from 5 mg/L before the use of road salt to 115 mg/L today. In Lake Mendota, salt concentrations increase about 1 mg/L each year. The good news is that the lakes are responsive to changes in salting practices. Concerted efforts by county and municipal governments over the past five years have helped to slow these trends, but more work is needed to protect and restore our freshwater resources.
For more information about the environmental impacts of road salt and other deicing chemicals, check out the Minnesota Stormwater Manual (PDF).
Data source: 2019 Road Salt Report, Public Health Madison—Dane County
*Wells and Private Drinking Water Graph: this figure compares chloride concentration trends in deeply cased wells, which draw water from the lower aquifer, and wells with short casings, which draw water from both the upper and lower aquifers. Check out the Public Health Madison-Dane County Road Salt Reports to learn more.
The growing pricetag of salt
During the winter of 2018-19, the Wisconsin DOT spent $40,683,595 on salt for state highways. That was the cost for 553,443 tons of salt and it doesn't include what communities, businesses and homeowners applied (source)!
Salt damages infrastucture
Salt alters the composition of soil, slows plant growth and weakens the concrete, brick and stone that make up our homes, garages, bridges, and roads. One ton of rock salt causes between $800 and $3,300 of damage to buildings, bridges and other infrastructure (source). Nationwide we spend over $5 billion annually to repair salt damage to roads and bridges and we're not keeping up (source).
Removing salt from water is cost-prohibitive
Once salt gets into water it is very difficult to remove. Treatment, like reverse osmosis or ion exchange, is costly to install and even more expensive to operate. It could cost millions or even billions of dollars, so preventing salt from entering our drinking water resources in the first place is the most cost-effective solution.
Winter salt use can also be hard on our furry friends. Road and sidewalk salt can cause irritation on toes, feet, and skin. Problems can also arise if a dog eats salt or licks their paws after a walk. Excess salt can cause toxicity concerns, throw off their electrolyte balance, or cause hypertension, cardiac arrhythmias, vomiting, increased urination, increased thirst, muscle tremors, or seizures. You can keep your pets healthy by shoveling first, and applying only the right amount of salt to keep sidewalks safe.