DURHAM -- Lake Ontario has a dirty image and there's a reason for it.

The noticeable stench and visible algae turn most people away from the thought of taking a refreshing swim on a hot day in this Great Lake. But children are children and where there's water, they will play.

As we near the end of July, more of Durham's beaches are beginning to face elevated levels of E. coli and other bacteria, making them unsafe for swimming or bathing. This is normal, said a public health inspector with Durham Region.

"As we move through the summer, as the water heats up, as we have heavy rainfall events, things like that, you will see more and more beaches posted," said Mike Pittman, a senior public health inspector with the Region. "At the beginning of the season, they're probably all open and looking good. As we move through the summer into August, you'll probably see the majority of them posted at one time or another."

Students working in the public health department over the summer conduct weekly testing at all 14 Durham beaches.

"So we go out about 15 metres into the water, usually between knee and hip height and then we use our reaching poles to get a further sample of the water," said Nadia Kyerematen. "We measure about 15 to 30 centimetres below the water and there is a specific type of pattern that we need to do it in. It's not just go collect and come back. There's specific ways we need to do it to make sure we get an accurate sample."

Each beach is separated into five sections, allowing for a more accurate reading than taking just one sample.

The results are posted online on Friday and a sign is also posted on the beach if it has been deemed unsafe for swimming or bathing. However, many residents enjoying the sun at Lakeview Beach in Oshawa recently had a hard time spotting the sign.

"There are none as far as I can see," said Gail Gushue, who brought her granddaughters to the beach. "I've just come right from the car, didn't see one sign, not a sign anywhere ... Absolutely should be more prominent. Then you can make your own decision as to whether you're swimming or not."

Even so, once they found out the beach was posted, not many parents, babysitters or grandparents were too worried about it.

"I'm not concerned about it. I can take them home and we'll bath them, put them in the shower, they'll be fine," said Shelley Phillips, a babysitter.

"She'll be fine swimming in the water," said Mrs. Gushue of her eldest granddaughter. "She's not drinking it, she's being very careful and staying in the shallow end so she's okay."

In Ontario, the Province has higher standards of acceptable levels of E. coli and other bacteria than in other provinces and even in other countries.

"In Ontario, the level is 100 E. coli per sample, in Canada it's actually 200," said Mr. Pittman. "There are places in Europe that will accept 500 and even 1,000 E. coli. So our standards in Ontario are quite stringent."

The Region also cautions people against swimming in area beaches after a heavy rainfall as there is likely to be a higher presence of E. coli within the first 48 hours after the rain has fallen.

"A lot of animal feces or dirt from the roadways and things like that gets washed into the lakes and it ends up elevating the E. coli levels," said Mr. Pittman. "So after a heavy rainfall event, we advise people to wait about 48 hours before they go into the water. Also on windy days when the water is being stirred up a lot because of wave action. If you go into the water to your waist and you cannot see your feet, we advise you not to swim. Just because there's a lot of turbidity and again the E. coli levels will be quite high."

Residents are encouraged to visit the Region's site before heading out to area beaches. The sample results are also posted on durhamregion.com every Friday.