In the last year, about 5,000 people in the United States were diagnosed with Legionnaires’ disease, which is a deadly bacterial lung infection for 1 in 10 people who get it according to a new CDC Vital Signs report.

Unlike most respiratory infections, Legionnaires’ disease is generally not spread from person to person — it is caused by breathing in small water droplets contaminated with Legionella. Looking back over all of the building-associated outbreaks that CDC investigated from 2000 through 2014 showed that almost all of these outbreaks were caused by problems that could have been prevented with more effective water management.

Other key findings in the Vital Signs report show that:

  • The number of people being diagnosed with Legionnaires’ disease in the United States grew by nearly 4 times from 2000 through 2014.
  • Approximately 80% of Legionnaires’ disease outbreaks that CDC investigated from 2000 through 2014 occurred in hotels, long-term care facilities, and hospitals.
  • Most Legionnaires’ disease outbreaks CDC investigated occurred because water systems in buildings were not well maintained; problems identified included process failures, human error, equipment breakdowns, or changes in water quality from reasons external to the building itself that led to growth of Legionella in the water.

CDC is urging building owners and managers to follow newly published standards that promote water management programs aimed at reducing the risk of Legionnaires’ disease. To support building owners and managers in this, CDC released a toolkit on Developing a Water Management Program to Reduce Legionella Growth & Spread in Buildings: A Practical Guide to Implementing Industry Standards. The toolkit interprets the guidance in ASHRAE Standard 188, provides a checklist and many examples to help identify where Legionella could grow and spread, and offers planning solutions to help reduce that risk.

Steps to develop a Legionella water management program include:

  1. Establish a water management program team.
  2. Describe the building water systems using text and flow diagrams.
  3. Identify areas where Legionella could grow and spread.
  4. Decide where control measures should be applied and how to monitor them.
  5. Establish ways to intervene when control limits are not met.
  6. Make sure the program is running as designed and is effective.
  7. Document and communicate all the activities.