A Chicago suburb on Wednesday issued a drinking water warning after officials found “elevated lead levels” in the drinking water of some homes, with residents advised to use filters, and get their children tested for lead.

The city of Aurora issued the public notice about the water Tuesday, saying lead service lines were contributing to the elevated levels. Between January 2026 and June 2026, the Water Production Division found that more than 10 percent of 100 samples collected exceeded the Environmental Protection Agency “action level for lead.”

“The lead action level is a measure of the effectiveness of corrosion control treatment in water systems,” the city said. “The action level is not a standard for establishing a safe level of lead in a home.”

Exposure to lead in drinking water can cause “serious health effects” for all age groups, the city’s warning said.

“Infants and children can have decreases in IQ and attention span, the warning said. “Lead exposure can lead to new learning and behavior problems or exacerbate existing learning and behavior problems. The children of women who are exposed to lead before or during pregnancy can have increased risk of these adverse health effects. Adults can have increased risks of heart disease, high blood pressure, kidney, or nervous system problems.”

Aurora officials went on to say that not all drinking water in the city contains lead. “Instead, it serves as a statistical representation of lead found in specific qualified homes that participate in the sampling program,” officials said.

A map of impacted service lines can be found here.

The notice said Aurora officials were continuing sample water to monitor lead occurrence. The city is also working to remove lead service lines and replace them with new corrosion control treatments which include the use of orthophosphate.

“Orthophosphate proactively reacts with lead to reduce the amount of it that can leach into drinking water, thus lowering potential exposure to lead when the water comes in contact with a lead service line,” the notice said. “This use of this treatment began in March.”

Residents are advised to use water filters and regularly remove and clean faucets’ screens or aerators. The city also encourages people in Aurora to run cold water, and get their water tested. Children should also be tested for lead levels, city officials said.