Providing safe water is our number one priority and a responsibility we share with you. Although the drinking water we deliver meets all federal and state water quality standards, in certain conditions, harmful bacteria can grow in pipes or other devices in your home or business if they are not properly cleaned and maintained.

Legionella is a microorganism found naturally in freshwater environments, but in high concentrations, it can cause a serious type of pneumonia called Legionnaires’ disease


How is Legionnaires’ disease contracted?

Warm, stagnant water, conditions found in hot tubs or cooling towers, provides ideal conditions for Legionella growth. Legionnaires’ is typically contracted through inhaling small droplets of water (aerosols), suspended in the air, containing the bacteria. Human-made systems that typically spread the disease include:

  • hot tubs
  • hot water tanks
  • large plumbing systems
  • cooling towers (air-conditioning units for large buildings)
  • decorative fountains
  • emergency showers
  • humidifiers.

Read more about the symptoms of Legionnaires’ disease.

Who Is At Risk?

Most healthy people are at low risk for contracting Legionnaires’ disease, but the probability of infection increases in the elderly – particularly for men. People with increased risk include:

  • those over 50 years of age
  • smokers, former smokers, and heavy drinkers
  • those suffering from chronic respiratory or kidney disease, diabetes, lung and heart disease, renal or hepatic failure
  • anyone with an impaired immune system due to immune system disorders or cancer treatment

What Can You Do?

As a homeowner, building manager or owner, you play a crucial role in controlling Legionella growth through routine system maintenance, from maintaining a minimal disinfectant residual, to flushing and cleaning of deposits, and ensuring that hot water stays hot and cold water stays cold. Learn more about what you can do to maintain the quality of water in your building:

More information on Legionella bacteria can be found on the World Health Organization and the Center for Disease Control websites.

Source: Customer Messaging on Opportunistic Pathogens in Plumbing Systems by the Water Research Foundation