What is Legionella?

Legionella is a bacterium first discovered after the 1976 outbreak of Legionnaires’ disease (a serious type of pneumonia) in Philadelphia at an American Legion convention.

Legionella can grow and multiply in building water systems, spreading to people through small water droplets in the air. There are currently no vaccines that can prevent Legionnaires’ disease.


Legionella Water Treatment

Legionella is found naturally in freshwater like lakes and streams. It becomes a health concern when it grows in man-made water systems that are not well maintained.

After Legionella grows and multiplies in a building water system, water containing Legionella can then spread in droplets small enough for people to breathe in.

Examples of building water systems that might grow and spread Legionella include:

  • Shower heads and sink faucets
  • Ice machines
  • Hot tubs
  • Hot water tanks and heaters
  • Large plumbing systems
  • Decorative fountains and water features
  • Cooling towers (structures that contain water and a fan as part of centralized air cooling systems for building or industrial processes)

Legionella Bacteria Growth Conditions
Legionella have been grown between 77 and 113°F (25 and 45°C) under laboratory conditions, with optimal growth between 77 and 108°F (25and 42°C).



Legionella Risk Management

Maintaining building water systems is essential to reduce the risk of Legionella growth and transmission.

Guidelines for Legionella Water Systems Control
ANSI/ASHRAE Standard 188, Legionellosis: Risk Management for Building Water Systems provides guidance for the risk management of Legionella and water systems. This standard provides a framework to develop a water management plan to minimize risk associated with illness.

The Cooling Technology Institute (CTI) has published a new document: Legionellosis Guideline GDL-159, Practices to Reduce the Risk of Legionellosis from Evaporative Heat Rejection Equipment Systems.


How ChemTreat Can Help with Legionella Control

ChemTreat works with our customers to develop Legionella water management plans in accordance with the risk management requirements set forth by ANSI/ASHRAE Standard 188.

ChemTreat Legionella Water Management Program Offerings Include:

  • ASHRAE 188-compliant Water Management Plans (WMP)
  • New York State and New York City-compliant Water Management Plans
  • Automation and control
  • Online real-time data logging
  • Legionella sampling services
  • Validation testing
  • Tower cleanings
  • Water Management Plan program training/education

For guidance around maintaining buildings during prolonged shutdowns, click here.


Other Cooling Water Treatment Offerings

Legionella bacteria is just one challenge companies face when managing their cooling programs. ChemTreat field representatives are experts in industrial cooling, with extensive experience in a variety of applications.

ChemTreat Cooling Water Programs

We offer cooling tower treatment programs such as:

To learn more about our cooling water treatment offerings, click here.


Potable Water Treatment Offerings

The Centers for Medicare and Medicaid Services (CMS) require healthcare facilities to reduce Legionella risk in their water systems to prevent cases and outbreaks of Legionnaires’ Disease.

Medicare and Medicare/Medicaid-certified healthcare facilities are expected to have water management policies and procedures to reduce the risk of Legionella growth and transmission.

CMS recognizes the ANSI/ASHRAE Standard 188 and its partner, the CDC Toolkit, as resources for developing water management programs.

ChemTreat partners benefit from our expertise in many areas of Legionella risk management:

  • Water management program development, including training and education
  • Validation testing and reporting, including Legionella sampling services
  • Remediation and disinfection support

Want to learn more about Legionella and biological control?