Aurora is set to introduce a new chemical into its drinking water to help control the lead levels in certain homes.
The chemical, called dipotassium orthophosphate, reacts with lead pipes to seal in the lead and prevent it from leaching into the water, according to Aurora Superintendent of Water Production Bob Leible. Plus, he said the orthophosphate is tasteless, odorless and safe for consumption.
“You would have to drink 40 liters of water in one sitting to get the amount of phosphorus that’s in a banana,” he said.
The new chemical is set to be added to Aurora’s drinking water system through the city water treatment plant starting in March, Leible told the Aurora City Council’s Committee of the Whole on Tuesday. Temporary feeds will introduce the chemical into the water at first, he said, as a permanent feed system is still several months away from being installed.
Tests done last year found high levels of lead in the drinking water of some Aurora homes.
Not all city drinking water contains lead, officials said at the time, and the water coming from the city’s treatment plant does not have lead in it. Some houses in Aurora just have elevated levels of lead in their water, as lead can enter drinking water from the pipes that connect houses to city water mains, which are called service lines.
The Illinois Environmental Protection Agency instituted new water testing standards in late 2024, changes which city officials said have contributed to certain homes in the city now exceeding the action level for lead. Under previous standards, only the first liter of water that came out of a faucet in a residential unit would be sampled to test for lead particles — but now, both the first and fifth liters of water must be sampled.
Higher rates of lead were found since the fifth liter of water spent more time in the service line, which in some houses is still made out of lead, so more of those particles dissolved in the water, city officials have said.
In addition to recent tests finding elevated levels of lead in some homes’ drinking water, the state EPA in 2022 told Aurora that it needed to do a corrosion control study to find a way to improve water quality, according to Leible. He said that study was recently completed with the help of national consultant CBM Smith.
To study how the orthophosphate would work in the distribution system, experiments were run using lead service lines that were actually removed from houses in Aurora, Leible said. Those experiments found that 2 milligrams of the chemical per liter of water was the most effective concentration, both from a water quality and cost standpoint, he said.
When the orthophosphate comes into contact with lead, it changes the chemistry of the water between the chemical and the lead, keeping the lead as part of the pipe instead of allowing it to leach into the water, said Leible.
Other cities throughout the United States and Canada have been using the chemical in their drinking water for decades, according to Leible. Chicago and Elgin are also starting to include orthophosphate in their water, he said.
Lead is toxic and can cause serious health problems, especially for children, according to the U.S. EPA.
Even at low levels, lead in a child’s bloodstream can cause developmental issues, the EPA’s website says. Lead is dangerous for adults, too, and is of particular concern for those who are pregnant because it can hurt the developing baby.
Water is not the only way people can be exposed to lead. Considering various risks of exposure, the state has identified many areas across the state, including in the Aurora area, where children are required to be tested for lead exposure.
These “Pediatric Lead Poisoning High-Risk ZIP Code Areas” can be found on the Illinois Department of Public Health’s website.
Aurora has been working to remove lead and galvanized water lines for years. Since 2018, the city has replaced 2,988 lead service lines, with more set to be replaced in the coming years, city officials said last month.
The state of Illinois is set to ramp up its lead water line replacement mandates starting in 2027, officials have said. Last year’s water rate increase should cover the cost of that state mandate, but a different federal mandate may raise that requirement even further and cost even more.
Aurora Mayor John Laesch said at Tuesday’s meeting that lead line replacements will have a “huge” impact on the city’s next budget cycle.
rsmith@chicagotribune.com
