WAUSAU, Wis. (AP) -- Hundreds of private wells in Marathon County have tested positive for coliform bacteria.

The bacteria is an indication of poor water quality and the potential presence of E. coli, which can cause flu-like symptoms.

The Marathon County Health Department has tested nearly 1,800 private wells so far this year and 14 percent have been found to be contaminated with coliform bacteria. The department's environmental health director, Dale Grosskurth, says he's not concerned about the findings because they are at, or below the state level.

The Wausau Daily Herald reports the state Laboratory of Hygiene found coliform present is about 15 percent of wells tested last year across the state.

Grosskurth says many of the positive tests are from older wells that don't have protective caps now required by law.