ST. CHARLES, Mo. – St. Louis City is now the sole provider of water for the city of St. Charles. This comes after the last operational well in St. Charles was shut down over the weekend. St. Charles leadership is concerned about a long-lasting problem.

Well #10 was providing one-sixth of the water demand for St. Charles customers. Summer demand is between six and seven million gallons each day. 

According to a statement from the city, the plant was closed on Sunday following a drop in the free level of ammonia in raw water. Chlorine (sodium hypochlorite) is introduced to the raw water and reacts with the free ammonia, producing mono-chloramine, which is the primary disinfectant in St. Charles’ water system.

Crews at the Elm Point plant have used free ammonia in this manner for nearly 70 years, the statement said. The city exhausted different options to spur an increase in ammonia to normal levels. The plant could no longer disinfect the drinking water according to Missouri standards.

The plant was producing a million gallons of drinking water per day for St. Charles residents and businesses.

John Phillips, superintendent of utilities for the City of St. Charles, tells FOX 2 that St. Charles is purchasing between 6 and 7 1/2 million gallons of water per day from St. Louis City.

“In the meantime, we are dumping all the water while we’re going through these processes to our sanitary sewer. So none of that water is going out to distribution,” Phillips said.

On Monday, the city contacted the Environmental Protection Agency, notified them of the drop in ammonia levels, and requested a federal investigation into the cause.

“What we suspect is Ameren in their process of cleansing the substation has released a lot of chemicals into the soil, which stripped out the contaminates,” St. Charles Mayor Dan Borgmeyer said. “But it stripped everything else out too. So now we have an aquifer that has no ammonia in it.”

City officials could not say for certain if the drop in free ammonia levels is connected to the ongoing contamination issues at Elm Point involving Ameren Missouri’s Huster Road Substation.

Earlier this year, the EPA said the substation was the source of the city’s water well contamination and was leaking carcinogens into the soil and groundwater.

An spokesperson for Ameren Missouri sent the following statement to news media in response to this latest development:

We have not received any data or analysis indicating that a report of an issue at the Elm Point Water Treatment Plant is connected to Ameren.  

We remain focused on remediation efforts at our substation. All work has been approved by the U.S. Environmental Protection Agency and is done under the agency’s supervision. We are committed to continued transparency, and further information is available at

Ameren Missouri

In the meantime, St. Charles has secured a store of liquid ammonium sulfate and will set up a temporary chemical feed pump and dosing system at the Elm Point treatment plant. Once that is completed, the water will be tested to see if it meets state standards. If so, St. Charles will restart water distribution at Elm Point.

“Once we add ammonia, and we can create that disinfection that we need, we will turn that well on,” Phillips said. “It’s just that we are now having to put a process in place that we’ve never had to have in place for the entirety of the operation of the water treatment plant.”

St. Louis City released a statement Monday night, saying it has plenty of water to help its neighbors to the west.

The City of St. Louis has abundant production capacity to meet the needs of the City of St. Charles. The City of St. Louis and the City of St. Charles has a long term agreement where the City of St. Louis has provided the City of St. Charles with clean, safe drinking water. The City of St. Louis is pleased to be in the position to be able to provide the City of St. Charles with the additional water.

St. Louis City