People get sick from Legionella by breathing in small water droplets containing the bacteria, not from drinking the water or contracting it from other people. Legionella can grow in plumbing systems when the water is warm and has low levels of disinfectant. Common ways people breathe in water droplets with Legionella are in a large building that uses a cooling tower, during showering, hot tub use, or exposure to decorative fountains. The risk of exposure to Legionella in a single-family home is low. Large buildings that have complex plumbing systems are at a much greater risk to Legionella growth.
Learn more about what you can do to prevent harmful bacteria like Legionella at your home or business:
Providing safe water is our number one priority and a responsibility we share with you. Although the drinking water we deliver to your property meets all federal and state water quality standards and requirements, the quality of that water can be affected once it leaves our pipes and enters a building or home, due to the unique interior plumbing system at your property. For example, in certain conditions, harmful bacteria can grow in your pipes, or other water-using devices in your home or business, if they are not properly cleaned or maintained. A very common bacterium found in pipes and water-using devices in homes and businesses is Legionella.
Whether you are a homeowner or a large facility manager, you have an important role in maintaining the quality of water on your property after it leaves the public system. Please see links at the end of this document for more information.
Has Tigard’s municipal water been tested for Legionella?
While Tigard doesn’t specifically test for Legionella, our water is delivered from a highly advanced water treatment process (Lake Oswego-Tigard Water Treatment Plant) that uses ozone and chlorine as a disinfectant to kill harmful pathogens, including virus and bacteria. Legionella is bacteria. The water is routinely tested by a certified laboratory throughout the Tigard Water Service Area to ensure that no pathogens are detected.
What are common causes and sources of infection?
- Cooling towers (structures that contain water and a fan as part of centralized air cooling systems for building or industrial processes)
- Hot tubs that aren’t drained after each use
- Decorative fountains and water features
- Showerheads and faucets
- Hot water tanks and heaters
- Large plumbing systems
How can you prevent Legionella in your building’s internal plumbing system?
To prevent the growth of bacteria like Legionella in your plumbing, there are actions that you can take that vary in complexity depending on what type of water system you have. Although the risk is low for a healthy person to contract Legionnaires’ Disease (in the home), there are simple precautions you can take to prevent the growth of Legionella.
Additional information from the CDC for large buildings, apartments, and facilities
- For more information about Legionnaires’ disease or the ecology of the Legionella bacteria, check out the CDC website