Why Water Systems Should Be On The Lookout For Legionnaires' Disease


Although substances like lead and per- and polyfluoroalkyl substances (PFAS) seem to receive the bulk of media attention, a longer-standing drinking water contaminant affects more people across the country and there’s reason to believe it’s poised to spread even further in the near future.
Legionnaires’ disease, caused by the waterborne bacteria Legionella, is currently the leading cause of reported waterborne disease in the U.S., accounting for nearly 60 percent of outbreaks over the last decade according to a new report by Smithsonian. Legionella grows naturally in source water and can threaten consumer health when it finds its way into distribution systems.
“Drinking fountains, hot tubs, sinks, toilets, sprinklers, showers and air-conditioning systems are among the common sources,” Smithsonian reported. “When inhaled at high enough levels, the bacteria can infiltrate the lungs and cause one of two forms of legionellosis, Pontiac fever or Legionnaires’ disease. The former is usually a fairly mild respiratory illness; the latter is far more commonly reported and estimated to be fatal in one in 10 cases.”
There may be a wide range of factors that are leading to a recent surge in reported cases: from around 1,000 cases in 2000 to more than 10,000 in 2018.
More testing is likely part of the cause. Climate change, which has brought longer summers and more stress on building cooling devices that can harbor the disease, could be contributing as well. And antiquated water systems, which also cause lead contamination, are probably contributors.
“As water travels through the distribution system and enters a building, it can lose disinfectant as well as interact with the materials, temperatures and designs of the building’s plumbing,” per Smithsonian.
And the problem may be exacerbated due to the COVID-19 pandemic.
“Some health experts express concern that a prior infection with the virus that causes COVID-19 could make a person more susceptible to Legionella,” Smithsonian reported. “But there’s an even more pressing concern connecting the two: Building shut-downs through the spring and summer have left warm water stagnant in pipes — a perfect environment for Legionella to multiply.”
Point-source filters, pipe flushing and chlorine boosting are water management and treatment strategies that could help in the face of this growing threat. They may soon become more common practices if Legionnaires' disease continues to proliferate.
To read more about how drinking water treatment operations deal with things like Legionella at treatment facilities, visit Water Online’s Drinking Water Contaminant Removal Solutions Center.