MOUND — The Minnesota Pollution Control Agency is advising people to avoid swimming in the largest Twin Cities area lake and two others nearby because of a release of untreated sewage.

Heavy rain forced the city of Mound to release raw sewage into the storm water sewer system Sunday. The agency gave the city permission to release the sewage in order to keep waste water from backing up into the basements of about 1,000 homes.

Reports said the waste water will likely make its way into Lake Minnetonka, Dutch Lake and Lake Langdon. And that will increase E. coli bacteria in those lakes.