Respiratory Infections

Swimmers are at risk for respiratory infections if they breathe in small droplets of water (mist) from a pool or hot tub that contains harmful germs. A respiratory disease caused by the germ Legionella is one of the most common waterborne diseases among people in the United States.

Legionella and Hot Tubs/Spas

Legionella is a germ that can cause a severe type of pneumonia (lung infection) called Legionnaires’ disease. Legionella can also cause Pontiac fever, a milder flu-like illness. Make sure hot tubs have the right disinfectant (e.g., chlorine) and pH levels to reduce the risk of spreading germs like Legionella. If you get symptoms of Legionnaires’ disease or Pontiac fever, see your doctor right away.

Hot tubs/spas can spread Legionella

Legionella is naturally found in water environments, especially warm water. People can get Legionnaires’ disease when they breathe in small droplets of water (mist) from a hot tub/spa that contains Legionella. Legionella can grow and multiply in hot tubs/spas that are not cleaned and disinfected properly.

Legionella can also be found in other human-made water systems such as cooling towers, plumbing systems, and decorative fountains.

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Older Woman Sitting in Hot Tub

People at risk

Certain groups of people are more likely to get Legionnaires’ disease:

  • People 50 years of age or older
  • Current or former smokers
  • People with chronic lung disease
  • People who have health problems or take medicines that lower their body’s ability to fight germs and sickness—such as people whose immune systems are weakened because of cancer, an organ transplant, or HIV

Protect yourself and others

Below are steps you can take to test hot tub/spa water and find out if it is being properly maintained.

  • Buy your own test strips. You can find these at your local retailer or pool supply store. Be sure to check the expiration date.
  • Check hot tub/spa water for free chlorine or bromine. Use the test strips to determine chlorine (3–10 parts per million [ppm]) or bromine (4–8 ppm) level and pH (7.2–7.8).
  • Talk to hot tub/spa operator or owner. If you find improper chlorine or bromine level or pH, tell the hot tub/spa operator or owner immediately.
Questions to ask your hot tub/spa operator
  • What was the most recent health inspection score for the hot tub/spa?
  • Are disinfectant level and pH checked at least twice per day?
  • Are disinfectant level and pH checked more often when the hot tub/spa is being used by a lot of people?
  • Are the following maintenance activities performed regularly?
    • Removal of the slime or biofilm layer by scrubbing and cleaning
    • Replacement of the hot tub/spa water filter according to manufacturer’s recommendations
    • Replacement of hot tub/spa water
Page last reviewed: February 7, 2020