Is Your Cooling Tower Safe From Legionella?

At Chardon Labs, we want to make sure that you are prepared and equipped to protect your cooling tower system and the people around it from harmful bacteria like Legionella.

What Is Legionella And Why Should I Care?

Legionella is a common water-borne bacterium. There several dozen known species. Some of the species, known as Legionella pneumophila, are potentially harmful to humans because they can cause pneumonia and Pontiac fever; otherwise known as Legionnaires’ disease.


Is Legionnaires’ Disease (LD) Contagius?

It is highly unlikely to contract LD from infected people.


How Do People Contract Legionnaires’ Disease?

People are infected by breathing water droplets and mist that contains the bacteria. Those water droplets are typically produced by shower heads, decorative fountains, misting machines, aspirating drinking water/ice, cooling towers for HVAC and manufacturing processes.


Is My Building At Risk For Legionella?

Legionella is a naturally occurring bacteria. It is found in ponds, lakes, rivers and streams occurs naturally in freshwater. When introduced to man-made water systems, it could create potential risks to humans.

It is not uncommon to find Legionella bacterium in drinking/domestic water systems. According to, expert Victor Yu, MD, Chief, Infectious Disease Section, VA Medical Center, Pittsburgh, PA, “Up to 70% of all buildings greater than three stories in the US may be contaminated with Legionella.”

There are multiple actions you can take to help prevent outbreaks of Legionella.


What Are The Best Practices, Guidelines, Regulations & Requirements for Legionella Prevention?

There are a variety of resources available. It is important to understand what practices are prescribed for your locale and industry.

Aside from specific regulations on cooling towers in New York City/State and the Center for Medicare Medicaid Service (CMS), most building owners rely on NSI/ASHRAE Standard 188-2018, Legionellosis: Risk Management for Building Water Systems. This document establishes minimum legionellosis risk management requirements for building water systems. These documents call for a Water Management Plan (WMP) as a foundation for Legionella control and safety within building water systems.


Do I Really Need A Water Management Plan For Legionella?

If not regulated, as discussed earlier, we refer to the Center for Disease Control (CDC) for guidance.

The CDC indicates that you should have a WMP if your building:

  • is a healthcare facility where patients stay overnight or houses or treats people who have chronic and acute medical problems or weakened immune systems
  • primarily house people older than 65 years (like a retirement home or assisted-living facility)
  • has multiple housing units and a centralized hot water system (like a hotel or high-rise apartment complex)?
  • has more than 10 stories (including basement levels)

Or if your building has,

  • a cooling tower
  • a hot tub (also known as a spa) that is not drained between each use
  • a decorative fountain
  • a centrally-installed mister, atomizer, air washer or humidifier

If you have any additional questions related to Legionella prevention and/or a water management plan, please reach out to us and we’ll be happy to discuss a plant to put in place for your facility.

Learn More About Our Legionella Testing & Control Services

Portrait of Matt Welsh, the co-president
Matt Welsh
Vice President, Water Consultant at Chardon Labs | Website | + posts

Matt Welsh is the Vice President and Water Consultant at Chardon Labs.  He helps consult a wide range of customers utilizing various methods of water treatment, from chemical to chemical-free approaches, large and small applications, and across a wide range of geographical influences.  With 20 years of water treatment experience, including a wide range of troubleshooting and service in potable water and non-potable HVAC and industrial applications, he is an expert in water treatment chemistry for cooling towers, boilers, and closed-loop systems.


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