Legionnaires’ Surge Spans NYC Mayor’s ZIP Code

Mayor Mamdani's official residence, known as Gracie Mansion, is located within the 10128 ZIP code, which is one of three ZIP code areas the health department is investigating about a community cluster of Legionnaire’s disease.

Juliette Fairley

Published: 7/6/2026, 1:12:39 PM EDT

Legionnaires’ Surge Spans NYC Mayor’s ZIP Code — A wrought iron gate secures the entrance to Gracie Mansion, on the Upper East Side in New York on July 28, 2014. (Richard Drew/AP Photo)

Several upscale Manhattan neighborhoods are under investigation by the New York City Department of Health for a community outbreak of Legionnaire’s disease that includes New York City Mayor Zohran Mamdani's residence.

The health department officially launched the investigation after confirming the first 2 cases on July 2, and by July 5, there were 18 cases in the Carnegie Hill and Yorkville neighborhoods, which span the 10028, 10128, and 10075 mail zip codes.

Mamdani's official residence, known as Gracie Mansion, is located within the 10128 zip code.

While the disease can progress quickly, it is treated with antibiotics. To date, no deaths have been associated with the cluster of cases.

“Thanks to Commissioner Martin and his dedicated staff, the collection of water samples, laboratory testing and community outreach has been ongoing throughout the Fourth of July holiday weekend,” Mamdani said in a statement posted on X.

The NYC Department of Health and Mental Hygiene did not respond to requests for comment by the time of publication. Dr. Alister Martin is the health department commissioner.

In a July 5 video posted on Facebook, the commissioner said his office is working to identify a source of the surge.

“Typically, it’s a cooling tower that is blowing water that has this bacteria,” Martin said.

Home air conditioners do not use water, but industrial cooling towers do, according to the New York City Health Department, and Legionella bacteria is known for growing in warm water found in places like hot tubs, whirlpools, cooling towers, and hot water tanks.

“Cooling towers are water systems usually found on the top of buildings,” a July 5 health department notice states. “They control the temperature of cooling systems, such as refrigeration. The cooling towers spray mist that contains the bacteria.”

The outbreak began last week at the start of a nationwide heatwave.

A health alert states that continuing to use home air conditioning units is important during extreme heat and temperatures reaching high levels.

Officials also noted that it remains safe to drink tap water, cook, and shower.

Legionnaires' disease presents as a type of pneumonia and symptoms can include a high fever, chills, muscle aches, a persistent cough, and shortness of breath.

Individuals experiencing symptoms are urged to call 311 or 844-NYC-4NYC to find a healthcare provider.

“Past community clusters have been caused by Legionella bacteria spreading through the air from the mist produced by cooling towers,” a July 2 press release states. “Building owners with any cooling towers that test positive for the presence of Legionella bacteria will be directed to conduct full remediation.”