Summer is almost here, and many of us will be heading to the beach to cool off in the ocean. Have you ever considered what you might be swimming in? According to the EPA, up to 3.5 million people in the U.S. become ill from contact with raw sewage from sanitary sewer overflows each year. Swimming in polluted water can cause stomach flu, skin rashes, pinkeye, respiratory infections, meningitis, hepatitis and even a form of pneumonia called Legionnaire’s disease.

There are a couple things you can do to decrease your risk of getting sick from swimming in the ocean. Flooding from storms can cause sewage runoff that can pollute costal bodies of water; health officials recommend waiting at least 72 hours after a storm before going back into the water. Research from the Santa Monica Bay Restoration Project found an increased risk of infection for people swimming within 400 yards of a flowing storm drain, so be aware of your surroundings and avoid swimming near storm drains.

Swimming in lakes and streams can also cause health risks. Last summer, 70 people swimming in an Oregon lake caught a stomach virus from an infected swimmer. Smaller bodies of water are also in danger of pollution from sewage, livestock waste, and broken septic systems, all of which can cause serious illness. When entering a lake, you should look out for blue-green algae, also known as cyanobacteria, which can cause stomach pain, vomiting, and digestive issues when swimmers come in contact with it.

Learn More:

9 Surprising Diseases You Can Catch In The Nation’s Oceans (The Huffington Post)
“Whether we like it or not, our nation’s beaches are not as clean as we would prefer them to be.

Health Threats from Polluted Coastal Waters (Beachapedia.org)
“The Surfrider Foundation, along with many county and state health departments has always advised the public never to swim or surf within 72 hours after a rain.”

From E.coli to Weil’s disease, the perils of outdoor swimming…and how to avoid them (The Daily Mail)
“Far from being the preserve of a few hardy types foolish enough to brave chilly British waters, outdoor swimming – in lakes, ponds, streams and lidos – is increasingly popular.”

Recreational Water Illnesses (CDC)
“Contrary to popular belief, chlorine does not kill all germs instantly. There are germs today that are very tolerant to chlorine and were not known to cause human disease until recently.”