Toolkit for Controlling Legionella in Common Sources of Exposure

The Toolkit for Controlling Legionella in Common Sources of Exposure (Legionella Control Toolkit) provides public health and building owners and operators with concise, actionable information on controlling Legionella in commonly implicated sources of Legionnaires’ disease outbreaks. It helps focus and improve Legionella control efforts and protect the safety of a building’s employees, visitors, and surrounding community.

Use this toolkit to:

Toolkit Modules

The toolkit is made up of six modules: five provide system-specific information and the sixth contains information about routine testing for Legionella. All modules were developed according to ASHRAE Guideline 12-2020, CDC Guidance, and other resources.

Routine Testing Module

The routine testing module contains practical information, such as values for performance indicators, a multifactorial approach to understanding test results, and a graphic to help assess how well-controlled a water system is for Legionella based on testing results.


The glossary includes terms and phrases used throughout the Legionella Control Toolkit.


CDC welcomes feedback on this toolkit. Email with your thoughts and suggestions.