ST. CHARLES, Mo. – The City of St. Charles shut down its largest water well due to contamination on Monday.

A spokesperson for the City of St. Charles said the Public Works Department closed the well in Elm Point Wellfield. The city has now shut down five of the seven wells. FOX 2 reported that when the city closed down four wells in October, it caused issues for residents who rely on the water. The city said the water treatment plant is now running at 25% capacity, and the city is buying more water from the City of St. Louis.

The spokesperson said action is needed now, and it will not wait for the EPA to hold Ameren or other parties accountable for spreading the contamination in the wellfield. The city has taken protective measures to provide safe drinking water for its residents. The spokesperson said that all the drinking water in the City of St. Charles is safe to drink.

The EPA stated in a public meeting on Nov. 17 that the source of contamination is unknown, and they are working towards finding the cause, according to a spokesperson with Ameren Missouri.