Recent storms flooded homes, stirred up water, and are fueling fast-moving currents, but they are also likely causing a spike in bacteria that could get you sick.

“There’s a pretty incredible current, with a lot of rapids that you would never expect to see on this lake in the middle of town,” said Matt Joyce, who jogs near Lady Bird Lake in downtown Austin.

Lady Bird Lake appears more brown than normal, water is flowing more quickly and passersby can see branches and other debris floating down the waterway. The Austin fire chief determined dangerous conditions on Lady Bird Lake, Lake Austin and the Colorado River downstream from the Longhorn Dam justify a waterway ban until Noon Wednesday.

The water is filled with more than dirt and visible debris.

“Anytime we get these rainfall and runoff events anything that’s on the surface of the ground is going to get washed into our creeks and lakes,” said Chris Herrington, an engineer with the Austin Watershed Protection Department. “Leaking wastewater or poop from animals, either domestic pets like our dogs and cats or wildlife, that’s all going to get washed into our creeks and lakes when it rains.”

Agencies test lakes and rivers for overall, long-term quality in central Texas. However, those tests are not meant as a judge of safe bacteria levels for individual swimming locations, according to Herrington.

“We can’t monitor everywhere,” said Herrington. “When there’s storm water runoff we use sort of that general rule of common sense. Stay out of the water, particularly when the flow is this high.”

Still, Herrington says the increased bacteria is only temporary. In general, he says the Highland Lakes maintain good water quality. Recent tests in Lake Austin, Lake Travis and Lake Buchanan all show test results within the state recommended limits. Those tests include an analysis of E. coli.

“It’s a good idea to wait until you can clearly see the bottom so you can see a lot of those submerged hazards,” said Herrington. “That generally means that the first flush of that most contaminated storm water has moved through the system and now you’re in that cleaner base flow. So you’re generally at less of a risk for recreating in water after the water is clear again.”

He says it’s typically a good practice to wait several days after it rains and until the water is clear before swimming in a lake or creek.