Institutional Water Treatment program service helps combat the spread of Legionnaires’ disease

Part of the Illinois Sustainable Technology Center’s Technical Assistance Program (TAP), the Institutional Water Treatment program, or IWT, provides unbiased, professional water treatment advice to facilities equipped with institutional water systems such as cooling towers, chillers, boilers, etc. IWT services support public health and safety while also facilitating cost savings associated with chemicals, energy, water, and maintenance in industrial and potable water systems. Services range from presenting on-site training and seminars to providing chemical specifications and making recommendations concerning a comprehensive water treatment program for the control of corrosion, mineral scale formation, and biological growth.

Recently, IWT has added to its list of valuable services by offering testing for Legionella pneumophila, the bacterium that causes Legionnaires’ disease–a potentially fatal type of pneumonia (lung infection). L. pneumophila also causes Pontiac fever, a less serious, flu-like illness. This bacterium can grow in building water systems, such as showerheads, sink faucets, cooling towers, ice machines, spa pools, evaporative condensers, hot water systems, and complex plumbing systems. People become infected by inhaling tiny water droplets containing bacteria, or by aspirating contaminated drinking water (accidentally inhaling water into the lungs or windpipe when drinking).

Legionnaires’ disease and L. pneumophila derive their names from a 1976 outbreak of pneumonia that occurred among attendees of an American Legion convention at the Bellevue-Stratford Hotel in Philadelphia, PA. There were a total of 182 reported cases, with 29 deaths, among the 2000 attendees. The cause of the outbreak was eventually determined to be a previously unknown bacterium, L. pneumophila, which had bred within the cooling tower of the hotel’s air conditioning system and subsequently spread throughout the building, infecting the Legionnaires. Once this bacterium had been isolated, the Centers for Disease Control (CDC) were able to retroactively attribute earlier outbreaks of disease to it, including earlier cases of Legionnaires’ and an outbreak of a flu-like illness at a health department in Pontiac, MI which became known as Pontiac fever.

According to the CDC, health departments reported nearly 10,000 cases of Legionnaires’ disease in the United States in 2018; however, Legionnaires’ disease is likely underdiagnosed, so this may underestimate the true incidence. Since no vaccines exist to prevent Legionnaires’ disease, the key to prevention is proper maintenance of building water systems to reduce the risk of growth and spread of bacteria. Regular maintenance testing of large distribution water systems provides validation that the water management program is effectively preventing the growth of L. pneumophila. Testing is also performed during outbreak investigations to identify the source of bacteria where reported cases of Legionnaires’ disease have been confirmed.

IWT offers on-site water sample collection and two laboratory test methods for L. pneumophila detection. The IWT laboratory is one of only six laboratories in Illinois that is CDC ELITE Certified for Legionella testing. The CDC Environmental Legionella Isolation Techniques Evaluation (ELITE) is a yearly program where laboratories demonstrate their proficiency in successfully identifying Legionella in water samples.

If you’re interested in exploring IWT’s testing service for your facility, you can download a flyer on the L. pneumophila testing service, visit the TAP web site, or contact Don Kueneke via email or phone at 217-333-3659.

How to safely flush plumbing systems and re-open facilities after shut-down

Plumbing pipes running along a concrete floor


by Jeremy Overmann, Chemist & Water Treatment Specialist
ISTC Institutional Water Treatment services group

The domestic plumbing systems in any building or part of a building that has been shut down or has experienced reduced use due to COVID-19 policies are at risk for causing disease and death due to the effects of increased water age, including corrosion and growth of bacteria. Before re-opening any such building, take steps to minimize these risks and include consultation with a licensed plumber.

The Illinois Department of Public Health (IDPH) has a general guidance document for returning these systems to regular use. In Attachment B (Section II, Step 2. b), IDPH recommends setting the water heater to at least 120 degrees F prior to flushing the domestic hot water plumbing.

We recommend a higher temperature of at least 142 degrees F as this will kill Legionella bacteria in the heater within 30 minutes. However, do not use water at this temperature for flushing if the building’s drain waste vent (DWV) materials and/or plumbing system components cannot handle this higher temperature.

WARNING: 142 degree F water can cause third degree burns in seconds. Note that Legionella bacteria can continue to grow at temperatures up to 122 degrees F.

The Environmental Science Policy and Research Institute has written a useful guidance document, Reducing Risk to Staff Flushing Buildings, which offers best practices for flushing building water systems in a way that keeps facility staff safe.

Use the IDPH guidance in conjunction with your facility’s Legionella Water Management Program (WMP). If none exists, we recommend writing a remediation and/or recommissioning plan, then later developing a full WMP. The Centers for Disease Control (CDC) offers a free training program on how to write a WMP and a toolkit to assist in developing a WMP.

Additional recommendations

Drinking Fountains: If these were shut off and/or not used for a period of time, they should be cleaned according to the manufacturer’s instructions before being used again for drinking.

Chlorine levels: The Illinois EPA requires a minimum of 0.5 parts per million Free Chlorine or 1.0 parts per million Total chlorine (also called Combined chlorine) in drinking water, unless a facility has been given an exemption (this is rare, but applies in some cases to facilities supplied with clean well water).

After re-opening, we recommend maintaining 142 degrees F or higher in all domestic water heaters and storage tanks, and 124 degrees F or higher in all recirculating domestic hot water systems for the purpose of reducing the risk of Legionnaire’s Disease. Note that delivered water at fixtures must meet local and state plumbing codes for maximum safe temperature to prevent scalding. The best way to achieve Legionella risk reduction and anti-scalding is to maintain high temperature in tanks and recirculating systems and employ thermostatic mixing valves just prior to point of use fixtures.

Finally, we recommend documenting all actions you take to prepare facilities for re-opening.

For more information

About the Institutional Water Treatment services group

The Institutional Water Treatment (IWT) services group, a unit of the Illinois Sustainable Technology Center at the University of Illinois, provides unbiased, professional water treatment advice to facilities equipped with industrial water systems including cooling towers, chillers, boilers, etc. If you need assistance with addressing system start-up due to COVID-19 or other related services, including legionella monitoring, please contact Jeremy Overmann  or Mike Springman.