They focus not just on making sure you're safe while swimming, but safe in what you're swimming in.
The Army Corp of Engineers sends water samples to the health department four times a year, and the water quality is getting better.
"The designated swim areas we, we identify as our safe areas to swim, and obviously we want to make sure that the water's safe there for people to swim," Michael Hurley, Chief Park Ranger for the Army Corps of Engineers said.
In years past, some samples have come back positive for E. Coli.
"We immediately close the swim beach, we let the state know and then we'll re-sample, and then in order to get it reopened we have to get two consecutive negative samples for E. Coli," Hurley said.
Well Park Rangers have a good idea what could cause higher levels of E. Coli in the water.
This year, Beaver Lake has had some of its cleanest water.
"I like to contribute a lot of that to what we're doing with the geese," he said.
They've started spraying the grass around the beach areas with a substance the geese don't like.
"We also use a laser at night to kind of shine around the lake and it's basically an annoyance to them."
Hurley said the Canada geese have been on the rise in the area for years, but with more people coming to the parks and feeding the animals, it's made them stick around.
But the new tactics are working, and the water is now cleaner thanks to the Rangers efforts.