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As road crews prepared for heavy ice and snow during the Jan. 24 weekend, Virginia Department of Transportation trucks pretreated major routes with brine to keep ice from bonding to pavement. After an inch of snow accumulated, crews shifted to rock salt, while plowing and sand remained the preferred treatments on subdivision streets.
The same materials that make winter travel safer can create lasting problems after the thaw. Brine, calcium chloride and rock salt eventually wash into storm drains, streams, rivers and drinking-water sources, where they can harm aquatic life, accelerate corrosion and increase treatment challenges.
That tension is the focus of Winter Salt Week, an annual awareness campaign held during the final week of January. Regional environmental and water organizations use the observance to promote “smart salt” practices built around a simple message: A small amount can control ice, but excess salt permanently pollutes water.
Del. Kathy Tran, D-18, introduced Joint Resolution HJ46 in the General Assembly to establish Winter Salt Week as a statewide observance. Her proposal would designate the week of the fourth Monday in January beginning in 2027.
Tran, a legislative member of the Interstate Commission on the Potomac River Basin, said the designation could help residents, businesses and governments learn to use appropriate amounts of de-icer. Winter salt improves road safety, she said, but overuse sends chloride into rivers, reservoirs and drinking water long after snow disappears.
Salt does not vanish after a storm
Runoff from roads, sidewalks and yards raises salinity in groundwater and waterways, threatening freshwater fish and other aquatic species. The Chesapeake Bay watershed supports more than 18.5 million people and an estimated 3,500 plant and animal species.
In Fairfax County, runoff ultimately reaches the Potomac River and Occoquan Reservoir, both drinking-water sources. Conventional drinking-water and wastewater treatment cannot remove salt. Reverse osmosis and desalination can do so, but Fairfax Water says those processes are extremely expensive to construct, operate and maintain, partly because they require large amounts of energy.
Salt also corrodes water and sewer pipes, bridges, roads, sidewalks and parking lots, adding to public maintenance costs. Chloride can damage household metal plumbing, fixtures and appliances such as dishwashers and washing machines.
High sodium intake is already a widespread health concern. More than 90% of American adults consume over the recommended 2,300 milligrams per day, with average intake reaching about 3,400 milligrams. Excess sodium increases the risk of high blood pressure, heart disease and stroke.
Sodium levels differ between Fairfax water sources
Fairfax Water serves more than 2 million customers and produces an average of 170 million gallons of treated water daily, with capacity for 345 million gallons.
Its 2025 water-quality report, based on samples collected in 2024, found sodium concentrations of 16 to 25 parts per million in finished water from the Potomac treatment source. Finished water from the Occoquan source ranged from 12.9 to 44.2 parts per million.
Fairfax Water attributes the difference partly to watershed size and land use. The Potomac watershed contains a greater proportion of forested land, and the river’s larger volume provides more natural dilution. The smaller Occoquan Reservoir can concentrate sodium more readily.
No state or federal maximum has been established for sodium in drinking water. Even so, Fairfax Water says rising salt concentrations in its source waters are unacceptable because of their effects on water quality, infrastructure and the environment.
A mugful can treat a driveway
One teaspoon of salt can permanently salinize five gallons of freshwater. Road salt, reportedly applied nationwide at about 20 billion tons annually, is a major contributor, although concrete weathering, sewage, animal waste, recycled-water irrigation, fertilizers and water softeners also add salt to the environment.
Residents can reduce winter pollution without leaving surfaces untreated. Fairfax Water recommends shoveling before ice forms and using salt only when necessary. One 12-ounce mug is enough for a 20-foot driveway, or roughly 10 sidewalk squares.
Salt should be scattered evenly rather than poured in clumps. Any material left after the ice melts can be swept up and reused. Because salt is ineffective below 15 degrees, sand or calcium magnesium acetate may provide better traction in very cold conditions.
Jamie Hedges, Fairfax Water’s general manager and CEO, said public participation is essential because winter salt ultimately reaches the drinking-water supply. Careful use by individuals can help protect local water, aquatic life and infrastructure, with small changes producing broader benefits across the region’s watersheds.