Vital Signs: CDC investigations show almost all outbreaks were caused by problems preventable with more effective water management.

There are no vaccines that can prevent Legionnaires’ disease.

Instead, the key to preventing Legionnaires’ disease is to reduce the risk of Legionella growth and spread.

Water Management Programs

Building owners and managers can use a water management program to reduce the risk of Legionella growing and spreading.

Building water systems and devices that might grow and spread Legionella include:

  • Showerheads and sink faucets
  • Cooling towers (structures that contain water and a fan as part of centralized air cooling systems for buildings or industrial processes)
  • Hot tubs
  • Decorative fountains and water features
  • Hot water tanks and heaters
  • Large, complex plumbing systems

Home and car air-conditioning units do not use water to cool the air, so they are not a risk for Legionella growth.

Developing a Water Management Program

CDC developed a toolkit to help building owners and managers develop and implement a water management program. Creating and implementing a water management program can reduce their building’s risk for growing and spreading Legionella.

Legionella and Hot Tubs

Legionella grows best in warm water, like the water temperatures used in hot tubs. Warm temperatures also make it hard to keep disinfectants, such as chlorine, at the levels needed to kill germs like Legionella. The levels of disinfectants and other chemicals in hot tubs should be checked regularly and hot tubs should be cleaned as recommended by the manufacturer.

Learn how you can test the water before you use a hot tub and questions you should ask your hot tub operator to determine whether a hot tub has been properly maintained:

Legionella and Motor Vehicles

Legionella can grow in the windshield wiper fluid tank of a vehicle (such as a car, truck, van, school bus, or taxi), particularly if the tank is filled with water. To prevent growth and spread of Legionella, use only genuine windshield cleaner fluid and follow the vehicle manufacturer recommendations, if available.