Staff at the city of McGregor in Clayton County found wastewater backing up at the wastewater treatment plant Tuesday morning.
The city’s wastewater operator said the discharge probably began early Tuesday morning when a valve plugged with rags. An estimated 10,000 gallons of untreated wastewater flowed over the yard of a nearby summer home before entering the Mississippi River on the south side of town.
The city stopped the discharge by 8 am.
The DNR encourages residents in the McGregor area to keep pets and children away from the discharge area until Thursday.