FOND DU LAC - As the floodwater finally recedes, there are concerns about a new health hazard in flooded areas. In Fond du Lac, a 13-year-old boy has a suspected case of sickness caused by E. coli. The boy’s mother told TODAYS TMJ4 reporter Lauren Leamanczyk that he's taking E. coli medication, but has not been tested for the bacteria. The doctor said he might have gotten sick while cleaning his family’s flooded basement. That is causing worry among others in the city. Marshall Will and his family have been sifting through the wreckage since water and sewage washed through his home. Now, he's worried about his kids catching E. coli. “It’s scary,” he said. “You never know where they're digging and playing." E. coli is often found in sewage. It can make you sick if it comes in contact with your mouth. Rock County officials also warned residents Tuesday after testing showed E. coli in the water. “They haven’t thought it more than property damage. They need to be aware there are other things in the water that can cause potential harm. I’m not saying it will, but it can," Joseph Shurhammer with the Rock County Health Department said. Authorities say hand washing is the best defense against E. coli. Sharon Gilles, whose Fond du Lac home is flooded, says she's been careful. “We had bleach wash sitting out. We stuck them in that. Go wash with soap right away. We had rubber gloves when we started bringing stuff out,” she told Lauren Leamanczyk Will says he and his neighbors don't need to add E. coli to the heap of trouble they're already dealing with. Click on the link under related content to see Dr. Richard Olds from the Medical College of Wisconsin discussing health concerns with flood waters.