What’s hiding in Well 15?

Not long ago, it was perfluoroalkyl and polyfluoroalkyl substances, or PFAS — the so-called “forever chemicals” that have been linked to health problems like liver damage, fertility issues and cancer.

PFAS were first discovered in Well 15, which serves between 10,000 and 15,000 residents on Madison’s east side, in 2017. In a 2018 study, the firefighting foams used at the nearby Truax Field were identified as a possible source of the contamination. Despite the city’s insistence that the PFAS levels weren’t dangerous, the well was shut down in 2019 in response to community concerns. Since then, those residents have received water from one or more of Madison’s 20 other active wells. But, in early September, a new, $5.9 million water treatment system is expected to go online, which will make Well 15’s water safe to drink again.

The changes to Well 15 — a stark, brick-and-concrete structure built in 1965 — aren’t noticeable from the outside. But when Joe Grande, a City of Madison water utility manager, visited the well as the new treatment system was being installed this spring, he says he felt like “a kid in a candy shop.”

The centerpieces of the new system are two parallel trains of two tanks each. Water passes through each train at a rate of 700 gallons per minute for a one-two punch of PFAS elimination.

The first tank contains 10 tons of granular activated carbon, or GAC, a material resembling coarse, black sand that’s typically made from organic materials like coconut shells or coal. When the water flows through the GAC, some of the PFAS stick to the carbon through the same chemical force that allows geckos to walk up walls.

The second tank is filled with ion exchange resin, a material that Grande likens, in both appearance and function, to water softening beads. The resin picks up any PFAS that didn’t stick to the GAC. After about 10 minutes, the treated water is pumped to a temporary storage tank, then on to its destination.

The new system is set up to operate remotely and continuously deliver up to 2 million gallons of water a day to the city. The system isn’t totally self-sustaining: Once the GAC and ion exchange resin are coated in PFAS, they have to be discarded and replaced.

“It has a certain capacity, you exhaust that capacity, and then you need to replace that media,” explains Grande. The GAC is replaced every nine or 10 months, and the ion exchange resin lasts about three years.

For many, the reopening of the well has been a long time coming. But Wisconsin has been relatively early to PFAS awareness and remediation. Only 11 states, including Wisconsin, currently have enforceable standards for PFAS in drinking water, though that number is now growing. (Wisconsin’s standards were set in 2022.) And no federal PFAS drinking water standards existed until last year.

States have until 2029 to comply with the U.S. Environmental Protection Agency’s new regulations. But on Madison’s east side, residents aren’t tossing coins into a wishing well and waiting — instead, they’re drinking clean water from one.

Well Informed 

The city delivers 24 million gallons of water daily, serving over 270,000 people in the Madison area.

Madison’s water is tested for 29 different PFAS. National and state PFAS limits are not exceeded at any active wells.

​COPYRIGHT 2025 BY MADISON MAGAZINE. ALL RIGHTS RESERVED. THIS MATERIAL MAY NOT BE PUBLISHED, BROADCAST, REWRITTEN OR REDISTRIBUTED.