Beach water testing: how it works

Recreational beaches on Lake Huron’s southeast shoreline are tested throughout the summer months by local municipalities.

To assist in the prevention and reduction of water-borne illness, local public health units also test some municipal beaches.

Health units follow a provincial Beach Management Protocol, which includes a pre-season assessment and routine (minimum weekly) sampling during the swimming season. The results of the sampling, combined with the knowledge from historical results, other environmental factors and any available epidemiological evidence are used to determine an appropriate response.

To assist the public in making an informed decision before swimming, the factors contributing to beach water quality are identified on signs at beaches, on websites or social media, and through traditional media, such as radio or newspapers. A beach will be posted as unsafe when the evidence suggests that the beach water is potentially dangerous to human health. One question asked recently is whether the declining lake levels will have an impact on the testing process or on beach quality itself. Inspectors have certainly noticed the change in levels but it has not had a significant impact on the sampling process. Samples continue to be collected from beach water at about a one-metre depth, although the sampler may have to walk a bit further to get to that point.

The second part of the question is harder to answer. Environmental factors, such as weather or the presence of waterfowl, can have a significant impact on the bacterial quality of the water. These factors vary from week to week and are recorded as part of regular sampling; however, it is difficult to separate these impacts from any smaller background changes that may be attributable to the lake level. All that can be said with certainty is that health units will continue to look closely at the evidence to determine if any additional factors are impacting beach water quality.