Why schools need to flush water systems before reopening

Facilities with stagnant water could have a certain type of bacteria growth, which can cause a deadly respiratory infection with severe pneumonia-like symptoms
By: | May 27, 2020
It is important for K-12 leaders to start Legionella treatment before reopening their campuses to lower the risk of transmitting Legionnaires’ disease, or legionellosis.gettyimages.com: Catherine Ledner

When reopening, schools that fail to flush their water systems could risk the growth and transmission of a bacteria that can lead to students exhibiting COVID-19-like symptoms or that can escalate the likelihood of older staff and faculty contracting deadly infections.

A bacteria growth known as Legionella that can cause a deadly respiratory infection with severe pneumonia-like symptoms in people over 50 years old or those with compromised immune systems easily grows in stagnant, 68-to-86-degree Fahrenheit water. The risk of transmitting the so-called Legionnaires’ disease, or legionellosis, on campuses increased during school closures since potable and nonpotable facility water systems were left idle. A Legionella outbreak could also trigger longer closures as well as health department violations and fines.

Legionella testing

“All buildings that have been left stagnant should first have their cold and hot water lines flushed thoroughly and then tested,” says Senior Vice President Glenn Strelau of Pace Chemicals, a company that specializes in building water treatment for HVAC boilers, chilled water systems and cooling towers. “The CDC already recommends performing a weekly flush of water fixtures to prevent Legionella from growing, so the fact that schools have been closed for months has created more of a problem.”


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Students, faculty and staff can be exposed to the bacteria when the contaminated water travels from heating tanks, for example, into water fixtures such as drinking fountains. “If you breathe in or ingest the bacteria and choke for whatever reason, then the bacteria can get into your lungs,” says Strelau. Contaminated water can also build up in plumbing stacks and HVAC systems.

To prevent legionellosis, schools are advised to undergo the ASHRAE Standard 188, a Legionella treatment that involves developing a water team to ensure testing development and implementation.

“I have not seen data about young students, for example, who have died from Legionnaires’ disease unless they have a weakened immune system,” says Strelau. “If they do get the infection in their lungs, they could just end up developing flu-like symptoms. But this can cause extra anxiety since those are the same symptoms that people infected with COVID-19 exhibit.”

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