28/05/2026
⚠️ New York City has just made Legionella testing in cooling towers three times more frequent and the reason why should concern building operators everywhere.
Following a Legionnaires' disease outbreak in Central Harlem in 2025, itself the latest in a series of outbreaks stretching back to a major South Bronx cluster in 2015, NYC has passed Local Law 159 of 2025, requiring cooling tower operators to test for Legionella monthly rather than every 90 days, effective 8 May 2026.
This isn't bureaucracy for its own sake. It's a direct response to people getting seriously ill, and in some cases dying, from preventable waterborne infections. Cooling towers create warm, recirculating water systems that are an ideal environment for Legionella growth, and the mist they release can carry bacteria directly into the surrounding air. In a dense urban environment, the exposure risk is significant.
The lesson here isn't just for New York. Wherever cooling towers operate (hotels, hospitals, office blocks, industrial facilities) the risk profile is the same. More frequent testing isn't a burden. It's the difference between catching a problem early and managing an outbreak.
Hydrosense PRO makes that level of testing practical, with on-site results in 25 minutes, no lab required.
Is your cooling tower testing programme keeping pace with the standard that regulators are now demanding?
🔗 Full details on the NYC regulation changes: https://hubs.li/Q04hGmqv0
Cooling towers are part of large air conditioning or refrigeration systems, often located on building rooftops. Cooling towers cool indoor spaces by removing heat from indoor air using water and evaporating it as mist into the outdoor air.