Beach sand may be more contaminated than water

"Recent research has revealed that beach sand contains high concentrations of E. coli and other fecal indicator bacteria, often greatly exceeding the concentration in beach water. Further, there is evidence that beach closings due to elevated fecal indicator bacteria may be linked to these sand populations... Beach water is routinely analyzed for E. coli and other fecal indicator bacteria to determine whether human sewage is present. When bacteria concentrations in water exceed a certain threshold, beaches are typically closed to swimming or swimming advisories are posted... A potential reason for many of these beach closings, and a complication for monitoring efforts is high concentrations of fecal indicator bacteria in beach sand. Bacteria are often present in high concentrations independent of any recent contamination events..."

Bottom line: if the sign says "No swimming," think twice about opting to have a picnic on the beach instead.