You can absolutely get sick from pool water, which highlights the importance of proper hygiene and maintenance. Illnesses contracted from swimming or contacting contaminated water are called Recreational Water Illnesses (RWIs). RWIs are not limited to pools but occur in any recreational water, including hot tubs, splash pads, lakes, and oceans. They spread when people swallow, breathe in mists, or have direct contact with water containing germs or irritants.
How Pool Water Becomes Contaminated
Pool water loses its protective barrier through a combination of biological introduction and chemical imbalance. Pathogens primarily enter the water directly from swimmers, even those who appear healthy, often through microscopic traces of fecal matter, vomit, or open wounds. Many common waterborne germs, such as the parasite Cryptosporidium (Crypto), are highly resistant and can survive in properly chlorinated water for over seven days.
Contamination also occurs when the pool’s chemical sanitation system breaks down. Chlorine’s effectiveness depends on the water’s pH level, which should be maintained between 7.2 and 7.6. If the pH is too high or the disinfectant level is too low (1 to 3 parts per million), pathogens can multiply rapidly. Organic matter from swimmers, including sweat, urine, and cosmetics, reacts with chlorine to form compounds called chloramines, which deplete the disinfectant and cause the strong, unpleasant “pool smell.”
The Most Common Recreational Water Illnesses
The most frequent illnesses acquired from contaminated water are gastrointestinal, typically caused by swallowing water containing bacteria, viruses, or parasites. Diarrheal illnesses are the most common RWI outbreak, often linked to chlorine-tolerant protozoa like Cryptosporidium and Giardia. Symptoms of these infections typically include watery diarrhea, stomach cramps, nausea, and sometimes a low-grade fever.
Other infections affect areas beyond the digestive tract, including the ears, skin, and eyes. Swimmer’s ear, or otitis externa, is a common bacterial infection of the outer ear canal that causes pain, itching, and fluid drainage. Skin infections, often referred to as “hot tub rash” or folliculitis, are typically caused by Pseudomonas aeruginosa bacteria and manifest as red, itchy bumps or pus-filled blisters.
Contaminated water can also cause eye irritation or conjunctivitis, commonly known as pink eye, which can be viral or bacterial. While most gastrointestinal symptoms are self-limiting and resolve within a few days, a medical professional should be consulted if diarrhea is persistent, bloody, or accompanied by a high fever or signs of severe dehydration. Immunocompromised individuals, the elderly, and young children are at a higher risk for severe complications and should seek medical attention promptly.
Essential Prevention Strategies
Protecting yourself and other swimmers from RWIs relies on a combination of personal hygiene and awareness of water quality. Every swimmer should shower thoroughly with soap before entering the water to remove dirt, sweat, and body oils that consume the pool’s chlorine. If you or a family member are experiencing diarrhea, you must stay out of the water for at least two weeks after symptoms have fully resolved to prevent spreading highly resistant germs like Cryptosporidium.
Parents of young children should take frequent bathroom breaks and check swim diapers hourly, ensuring any changes occur away from the poolside. It is also important to remind everyone to avoid swallowing pool water, as ingestion is the primary route for gastrointestinal infections. For private pool or hot tub owners, a simple test strip should be used to regularly check that the disinfectant and pH levels are within the proper ranges.