A cascade of deadly outbreaks of Legionnaires’ disease over the past two years has resurfaced an old question about how New York City manages its water supply. Should it build a mammoth, multibillion-dollar filtering plant for the billion gallons of drinking water that slosh into the five boroughs from the Catskill Mountains every day?<\/p>\n
According to Bob Bowcock, a water management expert and board member of the Alliance to Prevent Legionnaires\u2019 Disease, the answer is yes.<\/p>\n
He recently argued to city officials that the water supply is a source of dangerous Legionella bacteria that can make its way into a building\u2019s plumbing system, as well as rooftop cooling towers, which have been the subject of increased scrutiny and regulation because they\u2019re capable of broadcasting Legionella into the air and causing an outbreak.<\/p>\n
\u201cCooling tower regulation alone is not comprehensive Legionnaires disease prevention,\u201d Bowcock told members of the City Council\u2019s health committee in September, arguing that Legionella bacteria in drinking water is contaminating buildings and cooling equipment. \u201cThe water in the tower is the same water that runs through the entire system.\u201d<\/p>\n
Rising temperatures and increased rainfall are driving an uptick in the number of Legionnaires’ infections, according to several studies. And it\u2019s left scientists with many unknowns about how Legionella is growing and spreading in the built environment, said Annette Davison, an Australia-based water systems expert who is not affiliated with the alliance and does not advocate for filtration.<\/p>\n
\u201cBecause of climate change in particular, our systems are going to be changing,\u201d Davison said.<\/p>\n
City officials point to past studies that show only low levels of Legionella in the city\u2019s water supply and insist filtering is unnecessary because the bacteria is not at quantities that would pose a public health threat. And to Bowcock\u2019s opponents, the alliance he represents is nothing more than a nonprofit front for a cooling tower industry that would like to deflect lawmakers\u2019 attention away from the role its products play in outbreaks.<\/p>\n
\u201cThey have concerns that the focus on cooling towers will hurt their business,\u201d said Janet Stout, a leading expert on Legionella and cooling towers. She said filtering the city\u2019s water would be costly and do little to prevent future outbreaks, and she criticized the alliance for influencing regulations in other states that placed more responsibility on water utilities. She said cooling towers are the main cause of outbreaks and that public health departments should maintain a focus on them.<\/p>\n
Tax filings show the Alliance to Prevent Legionnaires\u2019 Disease is a who\u2019s who of cooling tower manufacturers. Over the past 10 years, its board has included executives from the largest cooling tower manufacturers in the country, including Don Fetzer, president of Baltimore Aircoil Company; William Bartley, president of Evapco; and Kenneth Mortenson, a manager of research and development at SPX Cooling Technologies.<\/p>\n
The group has long argued that the city is too narrowly focused on cooling towers, advocating instead for what it calls a \u201csource to tap\u201d approach that treats and monitors Legionella levels in drinking water. Eight years ago, as city lawmakers were weighing how to strengthen inspection requirements, the alliance\u2019s director of technology and science, Daryn Cline, testified<\/a> before the City Council.<\/p>\n \u201cEquipment-focused requirements will not address New York City\u2019s [Legionnaires\u2019 disease] issues,\u201d Cline told<\/a> officials at the 2018 hearing. \u201cFilter all the city water.\u201d<\/p>\n While he acknowledged under the Council’s questioning that the alliance was founded by cooling equipment companies, he did not disclose that he is also a longtime Evapco executive.<\/p>\n Cline, Fetzer and Mortenson did not immediately respond to a request for comment.<\/p>\n Bartley, Evapco\u2019s president and a founding board member of the organization, said Stout and other water consultants in favor of stringent cooling tower regulations have their own financial interests, especially regular testing requirements.<\/p>\n Stout was the founder of Special Pathogens Technology, a lab that conducts Legionella testing. City records show the company has over $2 million in contracts as of 2026 to provide Legionella testing services for the city\u2019s health department. Stout said she sold the company in 2021 and has advocated for Legionella testing, long before she started the lab.<\/p>\n Bob Bowcock, Alliance to Prevent Legionnaires’ Disease<\/p>\n New York City Council<\/p>\n More recently, some members of the Alliance to Prevent Legionnaires\u2019 Disease, including Bowcock, have applauded the city\u2019s strict rules for cooling towers while continuing to push for filtration. Bill McQuade, a global vice president at Baltimore Aircoil Company, is also the former president of the American Society of Heating Refrigerating and Air-Conditioning Engineers, or ASHRAE, which has become an authority in cooling tower regulations. New York City\u2019s own health code is based on ASHRAE\u2019s standards.<\/p>\n \u201cNo matter how stringent they are on the regulations in New York City on cooling towers, they\u2019re going to continue to have recurring outbreaks,\u201d McQuade said in an interview with Gothamist. He also testified at the City Council health committee\u2019s hearing in September.<\/p>\n It\u2019s unclear how much traction his arguments have had with local lawmakers. Samie New, a spokesperson for Health Committee Chair Lynn Schulman, said the committee is still reviewing alliance members\u2019 testimony and declined to answer questions about enhanced enforcement of building water systems and the possibility of filtering the city\u2019s tap water.<\/p>\n Unfiltered system<\/p>\n New York City has the nation\u2019s largest unfiltered water supply system. Most of the city\u2019s drinking water comes from 19 reservoirs and three lakes upstate and surrounding the Hudson Valley. To protect this vast drinking water supply, the city\u2019s Department of Environmental Protection has used a strategy of purchasing property that surrounds watersheds in the Catskill Mountains and implementing strict land-use restrictions. The federal government has waived a filtration requirement for the city ever since the federal regulations first went into place 23 years ago.<\/p>\n The city does filter some of its water. The Croton Filtration Plant, located in the Bronx, began operating in 2015. Up to 30% of the city\u2019s water supply on a given day arrives through the plant from the Croton Watershed east of the Hudson River.<\/p>\n Douglas Auer, a DEP spokesperson, said all of the city\u2019s drinking water is treated with UV radiation and chlorine. The water is also tested for Cryptosporidium and Giardia, two pathogens that cause intestinal illness.<\/p>\n While the agency does not regularly test for Legionella, Auer said a 2022 study by the agency found Legionella levels are not high enough to be a public health threat.<\/p>\n Auer said an additional filtration plant would not help prevent outbreaks of Legionnaires\u2019 disease. And Davison, the Australian water systems expert, said said there\u2019s not enough evidence to justify the hefty price tag of filtration for taxpayers.<\/p>\n But she said more testing and monitoring is needed at every stage of any municipality\u2019s water supply: at natural sources such as reservoirs, where water enters a city and the point it enters a building\u2019s plumbing.<\/p>\n \u201cWe need to refocus our efforts,\u201d she said.<\/p>\n City Council Health Committee Chair Lynn Schulman<\/p>\n Gerardo Romo \/ NYC Council Media Unit<\/p>\n The New York State Department of Environmental Conservation estimates that a filtration plant would cost between $8 billion and $10 billion to construct and $1 million a day to maintain. The Croton plant cost $3.5 billion<\/a> to build, more than three-and-a-half times more than initial estimates<\/a>.<\/p>\n But the Alliance to Prevent Legionnaires\u2019 disease says the daunting price tag is worth it to battle the growing threat of Legionnaires\u2019 disease.<\/p>\n In New York City, the number of Legionnaires\u2019 cases more than doubled in 2025, hitting a 10-year record high with 657 cases reported, according to city health department data.<\/p>\n Last year\u2019s high was only partly fueled by an outbreak in Central Harlem that sickened 118 people and killed seven. Even without the outbreak, the number of infections more than doubled from the 258 cases in 2024.<\/p>\n
\n<\/p>\n Case numbers have also climbed nationally over the past 20 years. The rate of infection has almost quadrupled. In 2005 the CDC estimated that fewer than one in 100,000 Americans were diagnosed with Legionnaires\u2019 disease. In 2025, it was close to three per 100,000 people.<\/p>\n Experts attribute the rise in cases to a variety of factors. Climate change and rising temperatures allow Legionella to thrive. Aging infrastructure is harder to clean and disinfect, making it more vulnerable to contamination. And an aging population both in New York City and nationally is more likely to get severely ill from Legionnaires\u2019 disease.<\/p>\n Chantal Gomez, a spokesperson for the health department, said 16 to 18 cases a year are connected to smaller clusters within buildings where people inhale mist from showerheads or faucets.<\/p>\n The vast majority of Legionnaire\u2019s cases are not investigated because they aren\u2019t connected to a larger outbreak or a shared water source.<\/p>\n For the Alliance to Prevent Legionnaires\u2019 Disease, the increase in cases \u2013 and the fact that health officials don\u2019t know the source of most infections \u2013 suggests that cooling tower regulations are not working and that the city should pay more attention to drinking water.<\/p>\n Bowcock said the group hired a water scientist to collect over 100 samples from hose bibs, faucets and outdoor fountains on the Upper East Side during the outbreak this summer. Test results showed that about 20% of samples had high levels of Legionella, he said.<\/p>\n Cooling towers on a building in Manhattan.<\/p>\n Caroline Lewis<\/p>\n Bowcock told lawmakers in September that Legionella in the water is contaminating cooling towers and indoor plumbing.<\/p>\n \u201cUntil we take a concentrated approach that’s systematic, that goes from source to tap, we’re going to continue to be back here year after year,\u201d Bowcock said at the hearing.<\/p>\n But Chris Boyd, a water consultant and former health official who authored New York City\u2019s cooling tower regulations, said it\u2019s impossible to draw any conclusions about the city\u2019s tap water from the alliance\u2019s samples because the water could have run through the buildings\u2019 plumbing before it was collected for testing.<\/p>\n Boyd said other researchers have drawn thousands of samples from a variety of water supply systems across several cities.<\/p>\n \u201cWhat they\u2019ve found uniformly across many studies is that there is no evidence that there is systemic risk of Legionella in municipal water systems,\u201d Boyd said.<\/p>\n Boyd does agree with one of the alliance\u2019s suggestions, however. It has proposed that the city require property owners create more comprehensive water management plans, detailing how they would test all water circulating in their buildings for Legionella and treat it when levels are high. Opposite of New Jersey and Los Angeles, current city regulations only require management plans for cooling towers.<\/p>\n Boyd said he also supports testing reservoirs after seasonal changes, like a heavy rain, which could lead to an uptick of bacteria and organic material in the water supply. But he said filtration is wasteful and unnecessary and that testing the water in buildings is a more strategic middle ground.<\/p>\n \u201cThat is where conditions to amplify [Legionella] exist,\u201d he said. \u201cThere is no harm in increasing surveillance sampling.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"A cascade of deadly outbreaks of Legionnaires’ disease over the past two years has resurfaced an old question…\n","protected":false},"author":2,"featured_media":364715,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[9,56,63,65,64],"class_list":["post-364714","post","type-post","status-publish","format-standard","has-post-thumbnail","category-new-york-city","tag-new-york","tag-ny","tag-nyc","tag-nyc-headlines","tag-nyc-news"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us-ny\/wp-json\/wp\/v2\/posts\/364714","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us-ny\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us-ny\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ny\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ny\/wp-json\/wp\/v2\/comments?post=364714"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us-ny\/wp-json\/wp\/v2\/posts\/364714\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ny\/wp-json\/wp\/v2\/media\/364715"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us-ny\/wp-json\/wp\/v2\/media?parent=364714"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ny\/wp-json\/wp\/v2\/categories?post=364714"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ny\/wp-json\/wp\/v2\/tags?post=364714"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}