Implementing Remediation Plans

Key points

  • Remediation is nearly always indicated whenever an outbreak of Legionnaires' disease occurs.
  • Remediation may also be indicated when control measures are ineffective or routine results indicate poor Legionella control.
  • Remediation may also be appropriate in response to unexpected events (equipment failure or acts of nature) that disrupt the water system.

Remediation options

Defining remediation‎

Remediation involves response activities taken to minimize the risk of Legionella growth and transmission. Remediation is intended to eliminate colonization within a building water system or device.

Remediation options can include:

  • Hyperchlorinating the potable water system
  • Draining and scrubbing devices
  • Superheating and flushing a simple device

Note, ASHRAE Guideline 12 recommends against superheating as a remediation method for potable water systems.


If an outbreak or illness is suspected, test in conjunction with public health in order to:

  • Confirm the presence of Legionella before performing remediation.
  • Confirm elimination of Legionella after remediation activities.

Tailor the remediation to structural characteristics of the facility and circumstances of the outbreak.

Base decisions on findings from the

It may sometimes be necessary to hire a consultant with Legionella-specific environmental expertise to help make decisions about or perform remediation.

Device-specific recommendations

Access specific remediation guidance for