Pseudomonas aeruginosa in swimming pools and spas

Pseudomonas aeruginosa (P. aeruginosa) is a common type of bacteria that can grow and multiply easily in water.

Characteristics of Pseudomonas aeruginosa

  • Organism size ranges from 0.5 µm – 1.0 µm x 1.5 µm – 4.0 µm.
  • Resistant to a wide range of antibiotics and disinfectants.
  • Grows well at temperatures up to 41 ˚C.

Pathogenesis of P. aeruginosa

Common P. aeruginosa infections include:

  • folliculitis – this is a pustular rash of hair follicles on the skin that occurs within 8 hours to 5 days after the event and usually resolves within 5 days. It is most common in heated spa-pools
  • otitis externa (swimmers ear) – most common for swimming pools
  • urinary and respiratory tracts infections
  • wounds and cornea infections.

Occasional symptoms of P. aeruginosa include:

  • head and muscle aches
  • burning eyes and fever - resembles inhalation of P.aeruginosa endotoxins.

Infection can occur to healthy individuals at levels of >1000 organisms/mL.

Environment and contamination sources

  • Ubiquitous in water, vegetation and soil skin shedding from infected humans is the predominant source of contamination in swimming pool or spa.
  • Warm or damp environments surrounding pools and spas can cause contamination, such as decks, drains, benches and floors.
  • P.aeruginosa tends to accumulate in biofilms in filters that are poorly maintained and in areas where swimming or spa pool hydraulics are poor such as under moveable floors.
  • Bathers are likely to pick up the organism on their hands or feet and transfer them to the water.
  • Elevated organic loads in spas (particularly skin cells) protect organisms from disinfection, reduce the residual disinfectant level and provide a source of nutrients for organism growth.

Risk management

There are a number of ways to mitigate risk of P.aeruginosa at an aquatic facility including:

  • maintaining adequate residual disinfectant levels in swimming pools and spas
  • frequent monitoring and adjustment of pH and disinfectant levels is essential
  • routine and thorough cleaning of swimming pool and spa interiors, surroundings and surfaces including pipe-work
  • using chlorination that is superior to bromination in controlling P.aeruginosa
  • strongly encouraging patrons to shower, before using a swimming pool or spa
  • controlling the numbers of bathers and duration of spa exposure.

More information

  • Environmental Health Directorate, Water Unit
    Postal Address: PO Box 8172, Perth Business Centre WA 6849
    Phone: 9222 2000


WHO - 2006, Guidelines for safe recreational water environments Volume 2 - Swimming Pools and Similar Environments

Last reviewed: 15-10-2020
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