For the first time in decades, residents of the city of Waukesha, Wisconsin, aren’t worried about water supply or quality, thanks to a historic agreement that allows the far western suburb of Milwaukee access to water from Lake Michigan, about 17 miles to the east.

The controversial agreement was significant because it marked the first time a community outside the Great Lakes basin was allowed to tap into Lake Michigan water under the terms of the so-called Great Lakes Compact. Approved in December 2008, the agreement regulates and protects against diversions of Great Lakes water from the 94,000-square-mile basin, says Dan Duchniak, general manager of the Waukesha Water Utility.

“It was a historic undertaking — the first of its kind,” Duchniak says of the approval, which required unanimous assent from eight governors of the states surrounding the Great Lakes: Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania and Wisconsin.

“It’s also the biggest water project in state history,” he says.

The agreement allows Waukesha to divert up to 8.2 million gallons per day of Lake Michigan water.

But there’s one key caveat: The city has to return the same amount of water it uses each day back into the Great Lakes basin, minus an allowance for “consumptive use” by residents and businesses. Waukesha achieves this by discharging treated water into the Root River, a 43-mile waterway that empties into Lake Michigan in Racine, located in southeastern Wisconsin.

Going the extra yard

But to avoid any negativity that might result from a net loss of water going back to Lake Michigan and to make the diversion proposal more attractive, Waukesha officials went one better and offered to return 100% of the water it receives to Lake Michigan. The amount it sends back every day is based on the previous year’s average daily water usage, Duchniak says.

“During a drought, we might not be able to pump 100% of the water back, but we’d make that up during spring and fall when there’s more rain,” he notes.

How does the city make up for the water lost to consumptive use? The treated water it sends back to Lake Michigan includes stormwater inflow and infiltration into sanitary sewers, which makes up about 20% of the water the city’s treatment plant handles every day. That more than accounts for the roughly 8% of water lost to consumptive use, he explains.

The city devised a system that prevents it from sending more water than required back into the basin. When the water that’s sent back to Lake Michigan reaches the required level, a pump that sends it there automatically shuts off and the rest of the treated water is discharged into the Fox River, he says.

“Returning the water via the Root River was a huge selling point,” Duchniak notes. “That provided some positive environmental impacts on the river, such as stabilizing river flows to reduce low flow periods and improving spawning conditions for salmonids, which results in increased angling opportunities within the Great Lakes.”

Major undertaking

Getting Lake Michigan water to Waukesha and back into the Lake Michigan basin required roughly $286 million in infrastructure, including 36 miles of underground pipeline consisting of mostly 36- and 30-inch-diameter ductile-iron pipe.

The system’s primary components are an 11-mile pipeline that carries water treated by the city of Milwaukee from a pump station in Milwaukee to Waukesha; two 8.6 million-gallon ground storage reservoirs in Waukesha; and a 25-mile pipeline that carries treated and subsequently aerated wastewater from Waukesha to the Root River, Duchniak says.

About 2.6 miles of the pipelines — 20 different sections in all — were installed via horizontal directional drilling, using high-density polyethylene pipe. Nearly 32 miles of the pipelines, which traveled through six different Milwaukee suburbs, were installed via opencut excavation.

“Very little property acquisition was required,” Duchniak says. “Most of the pipelines were built within existing public rights-of-way.”

The project was funded by a low-interest, roughly $137 million loan under the auspices of the federal Water Infrastructure Finance and Innovation Act and low-interest loans from the state of Wisconsin’s Clean Water Fund Program. Water rates were nearly tripled in order to pay back the long-term loans.

High radium levels

Waukesha’s water woes began developing back in the 1970s. At that time, the city obtained all its water from the St. Peter Sandstone Aquifer via 11 wells.

But a geological quirk — a thick layer of shale located in southeastern Wisconsin and northeastern Illinois — prevents water from naturally percolating through the soil and recharging the aquifer. That factor, combined with communities in both states over-pumping the aquifer, led to high radium levels in drinking water, Duchniak says.

Because it takes so long for Lake Michigan water and other water sources to percolate and recharge the aquifer, the Waukesha wells were pulling older and older water that had plenty of time to react with minerals and elements in the ground — including radium.

“And radium levels get higher and higher the farther down you go,” Duchniak says. “Our radium levels eventually were three times higher than allowed by federal drinking-water standards.”

After losing a court battle to change how the federal government determined acceptable radium levels, the city entered into a consent order with the Wisconsin Department of Justice to bring the water into compliance with radium standards.

“This was a long-term sustainability issue as well,” Duchniak adds. “We could’ve treated the radium. But as you pull water from deeper and deeper locations, other issues start to arise, including hitting brackish water with high total dissolved solids.”

Installing an expensive reverse-osmosis system to desalinate the water would’ve resolved that problem. But the reverse-osmosis process wastes about 20% of the water it treats, which in turn would require pumping 20% more water to compensate for that loss, further drawing down the aquifer, he explains.

“So we needed to address the long-term sustainability issue, not just the high radium levels in the water,” Duchniak says. “We figured it was better to spend money on a permanent solution.”

Long and winding road

So in 2002, city officials began considering their options. Eventually 14 alternatives were proposed, which then were narrowed down to three. And despite the daunting approval process, diverting Lake Michigan water was deemed the best solution.

Despite the water issues, Waukesha was lucky in one respect: It was located in a county (Waukesha County) that straddled the basin divide, which under the terms of the compact made it eligible to apply for a water diversion from Lake Michigan.

The approval process started in December 2015 with the submission of an environmental-impact study to the other seven states. After a full-court press for more than a year, and contending with dissenting environmental groups, the proposal was approved in June 2016.

“It was a very difficult, long and arduous process with a lot of moving pieces,” Duchniak says. “At one point, Jeff Scrima (the mayor at the time) and I traveled to four states — Michigan, Ohio, Pennsylvania and Illinois — in four days to meet with governors and their staffs.”

Infrastructure construction commenced in December 2020 and was completed in September 2023. The city abandoned all but four of its wells, he says.

“They’re available for emergency backup if something catastrophic would happen,” Duchniak says.

Lake water arrives

On Oct. 9, 2020, Duchniak pressed a button that started the city’s transition from well water to Lake Michigan water, concluding a roughly 15-year journey. The transition alone was a huge task as the utility strove to avoid public health issues, such as stirring up lead and iron particles, Duchniak says.

“To minimize the impact on residents, we came up with a transition plan to slowly and methodically move water through the system,” he explains. “That was important because changing the flow of water through a system can kick up a lot of buildup in the pipes, which can create problems.”

The utility also conducted a large public information campaign to tell the city’s roughly 72,000 residents what to expect during the transition, including temporary conditions such as reddish tap water and a noticeable chlorine smell, he says.

The utility even developed an interactive map on its website where residents could watch the transition’s progress in real time.

Residents also were notified they’d no longer need or should optimize water softeners because Lake Michigan water is significantly softer than well water. That resulted in another positive ripple effect: a major reduction of salt discharged into the Fox and Root rivers, he notes.

The transition to Lake Michigan water, which involved moving approximately 50 million gallons of water through more than 300 miles of water mains, took nearly three weeks to complete. The utility received only one complaint about water quality, which reflects the great work done by utility employees, Duchniak says.

“Our employees worked their butts off and did an amazing job,” he says. “Everything went off without a hitch — it was very impressive. It was a tremendous effort by our staff.”

Problem solved

Looking back, the magnitude of the project — from developing a solution to getting approval from the various states to the massive construction project — is not lost on Duchniak.

“It was a monumental undertaking,” he says.

But the results — better quality of life for residents, bolstering economic development and accommodating future population growth — made it all worthwhile. The city, which uses about 6 mgd of water a day, is unlikely to face water problems for the next 100 years, he says.

In addition, using Lake Michigan water will reduce aquifer pumping.

“We’re set,” Duchniak says. “We’re in a really good position with our supplier, the city of Milwaukee, which has an ample and sustainable supply of water. The Great Lakes aren’t going anywhere and we’re returning the water, so there’s no net water loss to the lake.

“This is exactly where we wanted to be when we started this process.”