ST. CHARLES, Mo. – This week, the Environmental Protection Agency will hold a public forum where people from St. Charles can talk about problems with the city’s drinking water and share their thoughts.

Last month, St. Charles Mayor Dan Borgmeyer said the city had to shut down two of its seven water wells in 2022—four since 2005—due to spreading chemical contamination.

At an Oct. 26 news conference, the mayor said the wells were contaminated with carcinogens and that Ameren Missouri was responsible for releasing chemicals under the ground that threatened the water supply.

But Borgmeyer stressed that the city’s water was still safe for drinking and other uses.

City leadership called on the EPA and Missouri Department of Natural Resources for oversight and remediation to the problem.

The EPA will host a “public comment period and public availability session” on Thursday, Nov. 17, at Memorial Hall. Residents can submit questions or comments by email to, or by snail mail at Assistant Attorney General, U.S. DOJ – ENRD, P.O. Box 7611, Washington DC 20044.

The St. Charles Wellhead District serves as the primary source of drinking water for the city. An Ameren Missouri transformer substation near the Elm Point plant has been leaking carcinogens into the soil and groundwater, Borgmeyer said, and there’s concern that contamination is threatening the other wells.

In the 1970s, Ameren Missouri used a scouring solvent called tetrachloroethylene to clean equipment at the substation, according to Paul Michalski, a senior hydrogeologist 212 Environmental. Ameren attempted to degrade the chemical in soil and groundwater. Two carcinogens were created in the process—cis-1,2-Dichloroethene and vinyl chloride—both of which are harmful to human beings.

For its part, Ameren Missouri said the source of this recent contamination is unknown, and that groundwater from the wells are tested every two weeks. In a statement, Ameren Missouri said it supports EPA oversight and is committed to protecting the groundwater in the area.

St. Charles can produce six million gallons of drinking water a per day, but is below half that at present.

Normally, 60% of St. Charles’ drinking water comes from the city pumps. The remaining 40% is purchased from other sources, like the City of St. Louis. Borgmeyer said St. Charles has had to purchase about $2 million of additional water from St. Louis over the past five years.

According to the mayor, the city needs a new water treatment system and to relocate its water wells, which the St. Charles Public Works Department estimates could cost upwards of $60 million.