Mickey Scott was canoeing at Bde Maka Ska in Minneapolis Wednesday. But when asked whether she would take a swim, she expressed concern about water quality.
"The lakes aren't a choice to come to as often for swimming," Scott said. "When I bring my granddaughter swimming somewhere I don't choose to come to the lakes. We go to a pool or go somewhere else where I think the water's safer."
Three beaches in Minneapolis — Lake Hiawatha Beach and Bde Maka Ska's 32nd Street Beach and Thomas Beach — and one in Chaska — Clayhole Swim Beach — have been closed in the past few days after routine testing found high levels of E. coli bacteria.
Minnesota doesn't require testing for bacteria at public beaches, but according to the state health department, about 10 counties and cities across the state have testing programs, including Minneapolis.
In Minneapolis the Park and Recreation Board decides when to close a beach for health reasons.
Director of environmental management Debra Pilger said every Monday from May to September they test for E. coli bacteria at a dozen beaches.
"And the purpose of that program is really public health protection at the beaches because if E. coli levels get too elevated it can cause illnesses in people."
High levels of E. coli are also an indicator that other harmful bacteria are likely in the water.
It's not unusual to have beaches closed during the summer, Pilger said.
"Especially if we've had a really wet summer where we have a lot of rain events because all that rain is bringing in stormwater runoff off the streets and the lawns and the beaches themselves and bringing all of that kind of dirty water into the lakes. And that's when our bacteria loads get really high."
Common sources of bacteria are goose feces on the beach, babies in the water with leaking diapers, or other animal waste that washes into the lake from storm sewers, Pilger said.
"At the East 32nd Street beach on Bde Maka Ska unfortunately, that is right near a big storm sewer outlet and it's probably one of the reasons that we've had some closures there this year and in past years."
It takes a couple of days to get test results when water is sampled for bacteria. But Pilger said following a simple rule can prevent illness caused by high levels of bacteria at the beach.
"We recommend that people stay out of the water for the first 24 hours after a rain event. If you've got a tenth of an inch of rain, I don't think you need to worry about it as much, but if we've been getting significant rainfalls, we talk about rainfall of a half inch or more in the last 24 hours, you may want to stay out of the water because of elevated bacteria levels."
Pilger said the closed beaches in Minneapolis will stay closed, until at least early next week.
At Bde Maka Ska Derek and Jan Johnson from Edina were at the beach with their dogs. Jan Johnson said she knew about the high E. coli levels and wouldn't let her grandchildren swim in the lake. But she said she wasn't concerned about the dogs.
"You know it's a big body of water, and they're saying it's from the rain," she said. "I don't know that I believe that it's that polluted here."
MPR News intern John Nguyen contributed to this report.