Swimming is a good exercise and being in a pool is a cooling and refreshing experience. The water is inviting but, in spite of being disinfected, the water could still be harboring pathogens and other substances harmful to people’s health when people come in contact with them through their skin, by swallowing water or inhaling water vapor.
What are the health risks of swimming in public pools?
1. Infectious diseases.
Because public pools are used by many people, a number of which have unhygienic behaviors, public pools are notorious in harboring pathogens. These behaviors include urinating, defecating, spitting, and not showering before swimming, by which pathogens from infected individuals come in contact with the water. Pathogens could also come from bird droppings, dead animals, decaying leaves, or contaminated rainwater.
- Bacterial – Legionnaires’ Disease is a dangerous, potentially fatal lung disease transmitted by the bacterium Legionella. Its symptoms are similar to those of pneumonia. It is transmitted when water is swallowed or water vapor is inhaled.
Swimmer’s ear is a bacterial infection of the ear canal when water enters it and is left to stay for a long time. The bacteria thrive in the water when the pool is treated with imbalanced levels of disinfectant and pH levels.
Gastrointestinal diseases, like salmonellosis (caused by the bacterium Salmonella), bacillary dysentery (caused by the bacterium Shigella), and food poisoning and diarrhea (caused by certain forms of Escherichia coli) could be contracted when water contaminated with feces is swallowed.
Urinary tract infection (UTI) could be acquired through contact with Pseudomonas aeruginosa in the water from a person having the disease.
- Fungal – Athlete’s Foot is transmitted through the skin coming in contact with pieces of skin from an infected person in the water, common showers, and changing rooms.
- Viral – Adenoviruses could cause gastroenteritis, respiratory infections, eye infections, and other diseases while rotaviruses could cause severe gastroenteritis and dehydration in young children.
Influenza could be contacted from carriers of the virus, through inhalation or physical contact.
- Parasitic protozoan – The diarrheal diseases giardiasis and cryptosporidiosis caused, respectively, by Giardia and Cryptosporidium are passed on from feces in the water.
2. Disinfectant by-products (DBPs).
Recent studies show that sweat, urine, saliva, hair, skin particles, feces, cosmetics and sunscreens, when mixed with chlorinated water, form disinfectant by-products (DBPs). These DBPs trigger genes to mutate, damaging the DNA and increasing cancer risk. DBPs can be absorbed through the skin, swallowed or inhaled.
3. Chlorine itself.
Studies show that too much chlorine, evidenced by its strong smell, causes lung irritation and increases the risk of developing asthma. 
Health risks of public pools could be minimized by:
- informing/teaching people hygienic behaviors when using public pools
- disinfecting pool water with chlorine in the right amount or with ozone and ultraviolet radiation, to kill parasitic protozoans
- fitting the pool with the correct filter, such as the pool filters by Davey or Onga, for trapping impurities and other debris that may harbor pathogens
- maintaining and repairing pools using quality supplies and equipment, such as be had from APS Rewinds and Sales.