The potential for bacterial contamination is the greatest during the first day following a rain event and swimming is not recommended for one to two days after the rain event. In other cases, however, the cause of high bacterial levels is not readily apparent. In these instances, the Board of Health attempts to identify the cause and suggests potential solutions. Some bodies of water are inherently subject to high bacterial levels due to their location or source of water. For example, inland lakes that receive their water solely from rain are subject to high surface runoff concentrations.
Surface runoff is likely to contain contamination.
In these cases, there would typically be no other water source available to dilute the concentration of the surface runoff or to move it out of the beach area. Risk of Illness When swimming or conducting other water activities during periods of high bacterial levels, the risk of becoming ill from contamination increases. Children, the elderly, and individuals with weakened immune systems are the most at risk. Flu-like symptoms such as diarrhea, abdominal cramping, fever, and dehydration can occur from exposure to contaminated water. Upper respiratory illnesses, such as ear, nose, and throat infections, may also occur.