Beach Health & Water Quality

Beach Monitoring Results

What do the test results mean?

When bacteria levels have risen to unacceptable levels, a beach advisory or closing will be issued. The Great Lakes states and provinces all adhere to similar but slightly different bacterial water quality standards. Nevertheless, all bacterial water quality standards are based on estimates that ensure a low risk of illness in people. For example, the U.S. Environmental Protection Agency (U.S. EPA) estimates that, at concentrations of 126 E. coli per 100 ml, 8 of every 1,000 swimmers will become ill.

U.S. EPA recommends issuing a beach advisory if E. coli counts reach this level. The Canadian federal guidelines recommend a limit of 200 E. coli/100 ml, whereas public health units in several Great Lakes states and in Ontario use a mean level of 100 E. coli/100 ml as the threshold for an advisory. Local public health units may develop and adopt their own site-specific guidelines as part of their public health code.

Real-time Beach Monitoring

Around the Great Lakes, several efforts are under way to reduce the lag time between the occurrence of a contamination problem and warning of the public through beach advisories. New methods may soon allow obtaining water quality test results within minutes to hours. In addition, public health officials are looking into ways of broadcasting beach water quality information faster and more efficiently to beachgoers and other users.

Hence BeachCast, an online beach closure forecasting system for the Great Lakes. This service enables local public health officials to report water quality information to the public as soon as it becomes available and, if required, to broadcast beach advisories immediately.