Health officials are keeping a close eye on popular beaches in the region, as summer kicks into full gear.

The Simcoe Muskoka District Health Unit collects water samples from about 40 area lakes every week. The samples are logged and then sent for testing at the lab.

“We collect about five samples at each beach and that's the minimum depending on the length of the beach, sometimes we collect more,” says Kristin Webb.

 “We’re looking for anything above 100 e-coli per 100 millilitres of water and we do what we call a geometric means,” says Karen Kivilahti of the health unit.

That's a number that the health unit arrives at after taking into account extreme high and low levels of bacteria in the water – giving them an average reading of the water sample.

“Some beaches are more prone to elevated levels of bacteria based on how shallow the water is, whether or not there is a lot of current,” says Kivilahti.

Murky water, heavy rainfall and extreme winds can influence the quality of water as well, which could lead to a posted listing. These listings advise that swimming in the water could be unsafe.

“Why is it not safe? Maybe it won't hurt me. I don't like to worry about things I can't necessarily control, I guess,” says James Marick Faith Brandringe. “I’d still swim in it, bottom line.”

The health unit says swimmers should always avoid swallowing water and some of the health risks include gastrointestinal and skin infections.

“We encourage people not to swim 24 to 48 hours after a heavy rainfall, which can wash things into the water from roadways and the sand.”