Key points
- Building owners and managers should confirm that their water management program (WMP) is working as intended (validation).
- One way to do that is to perform routine environmental sampling for Legionella.
Validation options
The WMP team determines how to validate the efficacy of the program.
The best method for validation of a WMP for Legionella is routine testing for Legionella over time. Testing for Legionella can provide critical information to ensure a WMP is operating as intended and Legionella is well-controlled.
Because of the vulnerable population served, inpatient healthcare facilities should conduct routine testing for Legionella to validate their WMP. Other facilities serving a vulnerable population should consider conducting routine testing as a best practice.
Routine environmental sampling
Routine environmental sampling for Legionella is performed proactively, not in the context of a case or outbreak investigation. It occurs as part of an effort to reduce risk of Legionella growth and transmission in building water systems. It's also one way to validate a WMP.
Decision to conduct routine sampling
WMP teams should base decisions about routine environmental sampling for Legionella on a variety of factors.
If the team performs validation using environmental sampling, it shouldn't be performed in isolation but as part of a comprehensive WMP.
Sampling methodology
Specific decisions about sampling frequency, location, and methodology are made by the team. Sampling plans are unique to each facility.
Note: The approach to routine sampling in the absence of disease and environmental sampling during an outbreak may be different.
Informed by environmental assessment
When and where to test should be based on an environmental assessment and data supporting the overall WMP performance. The environmental assessment helps the WMP team understand the facility's water systems thoroughly to effectively minimizing the Legionella risk.
Download CDC's Legionella Environmental Assessment Form for guidance on how to conduct an assessment.
Additional considerations about routine testing, such as test method and result interpretation are covered in the Legionella Control Toolkit.