Water from a critical source on Madison’s near west side could become too salty to drink in the next two decades if remediation efforts are not successful.
Well 14 is a 56-year-old well on University Avenue and has shown dramatic increases in sodium and chloride since 2000. Chloride levels have doubled since that year.
The well pumped 844 million gallons of water into the city’s distribution system in 2015 and serves the Spring Harbor, Glen Oak Hills, Hill Farms, Sunset Village, Regent, Dudgeon-Monroe and Vilas neighborhoods, in addition to Shorewood Hills and parts of UW-Madison’s campus.
Elevated contaminant levels are attributed to the use of salt on roads in the winter to reduce snow and ice, according to the Madison Water Utility. Each year, about 140 tons of road salt are used on the two-mile stretch of University Avenue between Segoe Road and Allen Boulevard. Additional salt is used on privately owned parking lots, sidewalks and driveways, and that is more difficult to regulate.
But even if salt use in the immediate area around Well 14 ceased, there is a large reservoir of sodium chloride that would keep Well 14’s salt levels rising.
Sodium levels at Well 14 registered at about 45 milligrams per liter, which exceeds an EPA guideline recommending drinking water not to exceed 20 milligrams per liter, according to the Madison Water Utility. Chloride levels measured at 125 milligrams per liter, which is 50 percent of the EPA’s secondary maximum contaminant level.
That contaminant level is all about how the water tastes, according to Amy Barrilleaux, a spokeswoman for the Madison Water Utility. Secondary maximum contaminants are ones that do not have a detrimental health impact, such as iron or salt.
“It’s an aesthetic standard,” Barrilleaux said.
But if current trends continue, water may be difficult to drink in 17 years because of the salty taste, according to the utility’s data. Barrilleaux said there is not a penalty if the water exceeds the secondary maximum contaminant level, but it is a “red flag” concern that customers may reject the water.
“It’s a slow moving problem that's impacting the taste of the water,” Barrilleaux said. “Our job is to deliver drinkable water. We don’t want to get to the point where people reject it.”
While it’s not a health hazard, high levels of chloride in water can have the potential to harm fish and other aquatic organisms, according to Madison & Dane County Public Health, as well as affect groundwater.
Well 14 is not the only one facing this issue. According to water utility data, wells on the near west and east side also have increased salt levels.
"Rising levels of chloride in our groundwater and lakes should be a cause of concern to all of us," Madison Water Utility General Manager Tom Heikkinen said in a statement. "As a region, we are on an unsustainable path with respect to wintertime salt use and we need to figure out how to solve this problem now for the sake of future generations."
The contamination levels have prompted the water utility to conduct a remediation study, but any fixes will likely be costly and difficult, according to the Madison Water Utility. Possible solutions range from drawing water out of a different part of the well, drilling deeper into the aquifer or in the most extreme case, abandoning use of the well.
“What we’re really concerned about is looking to the future at other wells,” Barrilleaux said. “We don’t want to have any more Well 14s in the city of Madison.”
The study is likely to begin early next year, Barrilleaux said. The county also included $20,000 in its 2017 budget for a chloride application consultant who will determine best practices for road salt application.
Barrilleaux said rallying the community around the issue is difficult because using salt on the roads is a public safety issue. One local coalition founded by the Madison Metropolitan Sewerage District called the Wisconsin Salt Wise Partnership aims to increase public awareness about reducing salt use.
“A community has to strike a real balance between how much salt is safe and how much salt is too much,” Barrilleaux said.
Rick Wenta, environmental protection lead worker at Public Health Madison–Dane County, said he has noticed more people talking about the issue in recent years. He is a lead author of the annual road salt report. But he said that local governments are responding to what the public wants, which is clear roads in the winter.
"There's a price that comes with driving on roads (in the winter) that are in the same condition as the summer," Wenta said.
Using road salt grew in popularity after the Wisconsin Department of Transportation started using it as as a deicer on state highways. The city of Madison started salting city streets in the 1950s, after the DOT implemented a “bare pavement” policy for state highways.
Bryan Johnson, the Streets Division’s public information officer, said the city wants to use as little salt as possible. Salt spreaders disseminate salt at 300 pounds per two-lane mile, which is “as little as we can put down and keep the roads open.”
He also said salt routes are only added with new major community resources such as a public school or hospital.
The city will also use sand in areas that are not on bus routes or near schools to improve winter travel and reduce salt use. An additional brining method that keeps the snow from binding to the pavement is used on select streets when the ground is dry before a snowstorm.
“You can scrape off (the snow) without needing to dump as much on top of it,” Johnson said.