Water rates in Naperville are in line to increase $2.54 a month for the average homeowner beginning June 1 as the city prepares to make required improvements to its wastewater treatment plant and maintain its water delivery system.
City council members gave preliminary approval to a plan for rate increases during a workshop in which they criticized an "unfunded mandate" from the Illinois Environmental Protection Agency that they say is driving much of the higher cost. Final approval of the new rates is expected to come later this month.
Increased revenue will help pay for work to meet a mandate included in the Springbrook Water Reclamation Center's next operating permit that requires the city to decrease the amount of the mineral phosphorus in treated outflow from roughly 3 milligrams per liter to 1 milligram per liter in 11 years.
Jim Holzapfel, water and wastewater utility director, said decreasing phosphorus output will help with an issue far downstream -- a "dead zone" roughly the size of DuPage County in the Gulf of Mexico in which almost nothing grows or lives, partially because nutrients such as phosphorus and nitrogen are contributing to an oxygen deficiency.
Meeting the phosphorus removal standard will require the city undergo a project estimated to cost between $40 million and $60 million, set to begin in 2025.
Within the water rate increase proposal, the city would add a phosphorus surcharge to set aside money for work to remove more phosphorus by adding a chemical to the treatment process or altering the biological environment within the plant.
City officials said the surcharge is a transparent way to ensure customers know where their rate payments are going.
"A significant amount of the increase is to save money for the unfunded mandate," Mayor Steve Chirico said.
During the first of five years covered under the plan, 50 cents of the total increase for the average residential customer -- or roughly 20 percent -- will go to the phosphorus surcharge, said Marcie Schatz, deputy city manager.
During the second year, the surcharge will increase to $1, or 40 percent of the total upcharge, and in the third through fifth years, the surcharge will be $1.80, or 60 percent of the total.
The rest of the increase will allow the utility to maintain the efficiency of its system by conducting annual capital projects, maintenance and leak testing to ensure water isn't being wasted.
The aim of the water rate plan is to collect half the cost of the phosphorus project from two sources -- the new surcharge and repayments the water utility is receiving from a $13.2 million loan it gave the electric utility in 2014. The other half is expected to come from a loan the city will take out closer to the project's 2025 start date.
"I like this balanced approach," council member John Krummen said. "You're saving some money for it ahead of time."
Council member Kevin Coyne asked whether the city would pursue the phosphorus removal project if not for the EPA requirement, especially because Holzapfel said there is not a human health concern with the mineral's presence in treated water. Coyne also asked if the talk of potential loosening of environmental regulations by President Donald Trump's administration could make the phosphorus requirement a thing of the past.
Holzapfel said the city would eventually pursue the project, but the EPA requirement is forcing an earlier time frame than officials otherwise would choose.
"I don't see this one going away," Holzapfel said.
Before the city's rate increase sets in, the utility anticipates passing along a separate increase from the DuPage Water Commission, which in turn is passing along a higher cost being charged by the city of Chicago for water from Lake Michigan. Holzapfel said this increase is expected to charge the average residential customer, who has a $65.07 bill, an extra $0.15 a month.