St. Joe SP - Monsanto Lake

Source Information

The Missouri Department of Natural Resources samples water quality at all designated swimming beaches in the state park system on a weekly basis during the recreational season. The samples are analyzed at the Environmental Services Program laboratory in Jefferson City, and results are posted online. Water samples are analyzed for E. coli, a common indicator species for bacteria. It is normal for E. coli and other bacteria to be found at naturally-occurring levels in ponds, streams, rivers, lakes and reservoirs. Elevated bacteria levels are frequently associated with heavy rains; however, there are a number of other sources that may contribute to elevated bacteria levels, which may pose a health risk. Water sample results can help visitors decide whether a particular beach is suitable for swimming, based on the bacteria levels. In accordance with state law, the Missouri Department of Natural Resources will post signs notifying visitors that swimming is not recommended if the geometric mean of the weekly water quality sample results exceeds the equivalent of 190 E. coli colonies per 100 milliliters of water (190 mpn/100 ml).