Cooling Tower Water Treatment Program per New Legionella CTI Guideline 159

The beginning of spring brings the beginning of cooling tower season. There are guidelines and even local regulations1 that must be followed to ensure proper cooling tower start-up and water treatment practices to maintain not only a tower’s physical integrity but proper operation to reduce the risk of Legionella bacteria growth in the cooling tower system. In February 2020, the Cooling Tower Technology Institute (CTI) released a new document titled Guideline (GDL) 159 – Practices to Reduce the Risk of Legionellosis from Evaporative Heat Rejection Equipment Systems 2. This new CTI guideline provides operational instructions for owners and water treaters of cooling towers and evaporative condensers to minimize the risk of Legionella bacteria proliferation and spread. To reduce the risk of Legionnaires’ disease, CTI Guideline 159 recommends that cooling tower water treatment operations implement the following practices including but not limited to: •Daily application of halogens/oxidizing biocides •Creation, implementation, and verification of a Water Management Program per ASHRAE Standard 188 and CDC •Monitoring strategies:

-Visual Inspections

-Total Bacteria sampling

Legionella Bacteria sampling

•Effective cooling tower shutdown and start up procedures

•Cooling tower cleaning and disinfection

•Documentation storage

A copy of Guideline 159 can be purchased from the Cooling Technology Institute through their Publications Page: Contact your Barclay Water Management representative today to ask how Barclay can provide industry best practices as part of your water treatment program.

1 “Protection Against Legionella: Cooling Tower Requirements.” New York State Department of Health, 2018,
2 “CTI Releases Comprehensive Legionellosis Guideline!” Cooling Technology Institute, Cooling Technology Institute, 19 Feb. 2020, .
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