Even though public swimming pools and your backyard pool have chemicals in them to keep them clean and the water crystal clear, there are several diseases and illnesses you could potentially get when swimming with other people.


The illness caused by this bacteria is usually mild overall, but can present itself in severe stomach cramps, upset stomach, diarrhea, fever, and vomiting. It can live in the water column and pass between people very easily. In many cases of shigella, antibiotics can be used to put an end to the suffering you are experiencing.

If symptoms are mild, you could simply rest as much as possible and let the bug pass on its own over 5 to 6 days. If it becomes worse, and dehydration, fever, or other physical issues set in, it’s a good idea to contact your doctor for their recommendations or treatment.

Hepatitis A

While many individuals are vaccinated against Hepatitis A, it can still be contracted in shared pools on some occasions. The virus will attack your liver so getting a shot of antibiotics won’t be helpful in this situation.

Symptoms can cover a wide range of things from general nausea and upset stomach, loss of appetite, and diarrhea to signs of jaundice since it affects the liver. If you have swam in a public or shared pool recently and start noticing signs of gastrointestinal upset, contact your doctor for their opinion.

E. Coli

Commonly found in food that has not been cooked or stored properly, E. Coli can also live in water for extended periods of time. If you allow animals to swim in your pool, such as the family dog or if wildlife such as ducks and geese land on the pool, they can cause messes that will put bacteria and viruses into the water.

There are many different strains of E. Coli and not all are dangerous. However, those that are can be very dangerous leading to severe intestinal distress, diarrhea, nausea, kidney failure, and more.

Legionnaires Disease

Caused by the Legionella bacteria, this disease won’t affect your intestines like the previously mentioned ones will, but will instead attack your lungs causing pneumonia. It’s commonly inhaled from splashed water or mist from water features such as fountains, foggers, and more.

Legionnaires is rarely a problem in pools that are properly treated with recommended chemicals, acids, and chlorine but natural water pools such as those left untreated and filled by rainwater can be a potential location of the Legionella bacteria.


Caused by a parasite known as Cryptosporidium, the illness known as Crypto can cause intense diarrhea and stomach cramping. If pets or young children that are not yet toilet trained are allowed to swim in the pool, Crypto is a possibility.

The best protection against Crypto is to ensure the pool is properly treated with chlorine, and that pets and very young children are not allowed to soil the water with fecal matter.