Public and private hot tubs are a popular recreational activity, but they require careful maintenance to ensure a safe swimming environment. The state of Iowa has strict guidelines for the operation of public facilities to prevent waterborne illnesses. Owners of private hot tubs should be aware that hot temperatures encourage bacterial growth. Pseudomonas aeruginosa is a common bacterium that may cause infection and can indicate that disinfection levels have not been properly maintained.

Pseudomonas is found in the environment and may be present on human skin, hair and in feces. It is the major cause of infections commonly known as “hot tub rash” and “swimmer’s ear”. Symptoms of Hot Tub Rash (Pseudomonas dermatitis) include Itchy spots on the skin that become a bumpy red rash, rash in areas previously covered by swimsuit, pus-filled blisters around hair follicles. Symptoms of Swimmers Ear (Otitis externa) include pain when infected ear is gently tugged, itchiness inside the ear, pus draining from the ear. Most hot tub rashes clear up without medical treatment. If the rash lasts longer than a few days, contact a health care provider for treatment. If you suspect that you have swimmer’s ear, contact a health care provider for treatment.

Pseudomonas can multiply quickly when water disinfectant levels drop, so testing your hot tub’s disinfectant and pH levels is also critical. Test kits or strips may be purchased at pool and spa supply stores. You may also submit a water sample for analysis to a laboratory. If the water sample is positive for Pseudomonas aeruginosa, immediate action should be taken to evaluate the cause. The hot tub should be drained, cleaned, and disinfected and the filter cleaned and disinfected (or replaced). Refill the hot tub and bring disinfectant residuals back to normal levels. The chlorine level should be 2.0 ppm to 8.0 ppm and the pH level should be 7.2-7.8. After the hot tub’s disinfection level has returned to normal, collect and submit a recheck sample to ensure Pseudomonas is no longer present.

For additional guidance or questions, please contact Johnson County Public Health at 319-356-6040 and ask to speak with a swimming pool and spa inspector.