MOREHEAD CITY, N.C. (WNCN) — As Labor Day weekend approaches, North Carolina recreational water officials are advising people not to swim in waters off the state’s coast in the aftermath of Tropical Storm Idalia.

Following weather events, stormwater runoff can lead to elevated levels of harmful bacteria draining into coastal waters that people use for recreational activities.

According to a release from the North Carolina Department of Environmental Quality, people should avoid swimming near ocean outfalls, even if no sign is posted. The wet sand where floodwater is pumped should also be avoided.

“Severe weather events like tropical storms and hurricanes bring excessive amounts of rain, storm surge and cause extreme flooding. These conditions increase levels of harmful bacteria in our coastal waters that can cause illness,” said Erin Bryan-Millush, manager of the N.C. Recreational Water Quality Program,. “The sources of bacteria can vary and include failing septic systems, sewer line breaks and overflowing manholes.”

Though state officials say they do not have immediate confirmation from laboratory tests that disease-causing organisms are currently in North Carolina’s waters, the chance of contaminated levels has increased due to Idalia. As a result, the risk of adverse health effects from swimming in these waters is also up.

People are asked to avoid swimming in these areas until testing samples show bacteria results within the state’s and the Environmental Protection Agency’s standards. According to state officials, testing will start when conditions are safe and areas are accessible.

The advisory will be lifted when results become available.