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Schools, gyms, and businesses have sat mostly empty for the past two months. They’ve been mostly quiet while everyone was at home. At a glance, they might appear lifeless. Look a little closer, however, and you might find that lifeless isn’t quite life. There are things that are living behind closed doors, oblivious to the slowdown that’s upended human life. They’re all around: on the floor, in the air, even living in the walls. They’re even in the pipes — and some might pose a risk to your health. Spoiler Alert: Legionnaires’ disease and COVID-19 are both concerns right now.
Yes, we’re talking about bacteria. The world around us, after all, is saturated with them. Most of the microbial life we share space with is either harmless or beneficial. They’re little kingdoms of no concern to us. Some varieties, however, can pose a risk to human health — such as legionella, the bacteria which cause a deadly pneumonia known as Legionnaires disease.
Legionella bacteria, which thrive on the moisture that comes with plumbing and HVAC systems, thrive in damp environments, growing in pipes or water features that harbor some stagnant water.
Why stagnant water? According to the CDC, stagnant water can dip down into temperature ranges where legionella thrives. Stagnant water can also see reduced concentrations of disinfectants like chlorine which would otherwise inhibit the growth of legionella. Stagnant water is still, rather than moving, which makes it easier for bacteria to form protective biofilms on the internal surfaces of plumbing.
After two months of lockdowns, stay-at-home-orders, and other measures, the plumbing in office buildings across America is likely harboring stagnant water — and potentially legionella bacteria as well.
Warnings as facilities reopen
The potential risk of legionella has not gone unnoticed. Several news outlets have published articles warning about the risk of plumbing that’s gone unused over the past few months. The New York Times published a piece featuring the voices of public health officials and researchers who warned that many facilities aren’t designed for extended periods without use.
“The buildings aren’t designed to be left alone for months,” Dr. Andrew Whelton of Purdue University told the NYT. He’s one of the authors of a study that’s been accepted for publication in the journal AWWA Water Science looking at the potential public health implications of plumbing after an extended lockdown.
The big finding of that article? We don’t know that much yet. The literature on extended plumbings shutoffs is relatively sparse. This is new territory for everyone. What we do know, according to the paper, is that extended water shutoffs decrease the effectiveness of disinfection agents in the pipes. Those disinfection agents may leave dangerous byproducts as they decompose. Pipes might corrode faster than they normally would. All the while, opportunistic bacteria are given more opportunities to establish themselves — changing the ecology of the pipes, potentially creating dangerous byproducts themselves, and building up their populations, increasing the likelihood of sickness when the water system is eventually reactivated.
Dr. Whelton isn’t the only researcher investigating the public health implications of plumbing shutoffs. An article published in Reuters mentioned a preprint study that’s been submitted by Chinese researchers to the Lancet.
Although it’s important to keep in mind that the study has not yet been peer reviewed or published, its findings were striking: twenty percent of coronavirus patients, they found, were also infected with legionella. Both legionnaires and coronavirus cause pneumonia; one disease may leave someone at higher risk for the other, and together the illnesses may be more deadly than each would be on their own.
The Chinese study isn’t the only instance of coronavirus and legionnaires showing up together. According to Reuters, doctors in Japan have documented a case of a man infected with both coronavirus and legionella bacteria after taking a cruise on the Nile River.
Preparing for reopening
There’s no one-size-fits-all solution for legionella and other dangers that may be lurking in the pipes as different businesses reopen. Several things can be done, however, so that businesses are as prepared as they can be to turn their pipes back on.
The CDC recommends several measures. Firstly, they say that businesses should develop a plan for dealing with legionella and other shutoff-related problems while reopening. There are plenty of resources on the CDC’s website to help specific business owners do so.
Secondly, they recommend checking the water heater at a facility — a common reservoir of legionella bacteria. It’s important that the water heater is hot enough to prevent the growth of undesirable bacteria — typically that means a temperature of at least 140 degrees.
Similarly, the CDC recommends checking on the maintenance and condition of other water fixtures, including drinking fountains, fire suppression systems, pools, hot tubs, water towers, etc.
Thirdly, they recommend doing a flush using both hot and cold water. Taking this precaution should help to clear some of the bacteria that may be present out of the system.
What isn’t clear is whether flushing with water is sufficient on its own to clear out dangerous bacteria from the pipes. There’s good evidence that it works for mainline plumbing systems; some fixtures, however, might require more specialized attention, either in the form of a chemical flush or a more aggressive cleaning.
If you’re a business that’s seeking to reopen and you’re worried about bacteria like legionella in your pipes, we recommend starting with the CDC’s website. The most important parties to do something — legionnaires is a serious, deadly disease and it should be treated with respect.
By: Sean McNulty