Independent testing finds 20% of NYC buildings contain Legionella bacteria

Independent environmental testing has revealed that nearly 20% of water samples from New York City buildings contain Legionella bacteria, including the highly pathogenic Legionella pneumophila serogroup 1 (LP1), which was linked to the recent outbreak in the Upper East Side. The findings, commissioned by the Alliance to Prevent Legionnaires' Disease (APLD), highlight the need for broader testing and prevention measures in the city's water distribution systems.

According to the APLD, an independent consultant conducted the tests in mid-July, analyzing 109 samples from buildings in zip codes 10128, 10028, and 10075, which were identified as the outbreak area. The results showed that Legionella was present in 19 buildings, including 10 exterior hose bibs, seven sinks, one shower, and a decorative fountain. The concentration of Legionella ranged from less than 1 to 390 CFU/mL, with the bacteria being detected in all three sampled zip codes. Additionally, the samples revealed very low chlorine treatment residuals, averaging only 0.12 mg/L, which is below the Environmental Protection Agency (EPA) recommended level of 0.5 mg/L.

"The findings from this testing are alarming and should serve as a wake-up call for New York City officials to reassess their current prevention strategy," said Bob Bowcock, a board member of APLD and founder of Integrated Resource Management, a water system consulting group. "Cooling towers are just one part of the water system, and you cannot rule out a point of exposure that has not been tested."

Bowcock, along with other APLD board members, testified at the September 2 New York City Council hearing, questioning the city's focus on cooling towers as the sole prevention strategy. "New York City tested 183 cooling towers but has not publicly identified comparable Legionella testing of distribution system water or building fixtures and plumbing systems," Bowcock added. "This narrow focus could be missing other critical exposure points."

The APLD's findings raise concerns about the comprehensiveness of New York's current prevention strategy. With the city continuing to grapple with one of the country's highest Legionnaires' disease burdens, and 96% of cases being sporadic, the organization advocates for a more integrated approach to water management. According to APLD, other states have implemented more robust safeguards, including minimum disinfectant-residual standards for water treatment and full building water management plans.

"We encourage officials to adopt a more comprehensive Legionnaires' prevention plan following national recommendations and best practices," Bowcock stated. "Given the significant toll of this disease in New York, it is imperative to implement source-to-tap policies similar to those in place in other jurisdictions."

The APLD, founded in 2016, is a nonprofit organization dedicated to reducing the occurrence of Legionnaires' disease through education, collaboration, public policy, and science-based prevention strategies. The organization brings together experts in public health, engineering, medicine, water treatment, environmental health, and industry to develop practical solutions that prevent outbreaks before they occur.