By Gus Saltonstall
An Upper West Side building’s hot water system has tested positive for Legionella bacteria, which cause Legionnaires’ disease, according to a memo from the building sent to residents on Friday afternoon, shared with West Side Rag.
The building in question is The Ardsley at 320 Central Park West, between West 91st and 92nd streets.
“Dear Shareholders and Residents, We are writing to inform you that recent testing detected Legionella in samples collected from the building’s domestic hot water system,” reads the memo to the building’s residents. “The co-op has retained Metrogroup, a qualified water-management consultant, to assess the domestic hot water system.”
“Following its evaluation, Metrogroup recommended that the domestic hot water system be disinfected and flushed,” the note continues.
The building’s hot water system will be disinfected and flushed on Thursday, July 16. On that day, residents should not use hot water until they are notified the process is complete, according to the memo. The evaluation for Legionella within the UWS building’s hot water system was done independently by the owner, and not by the New York City Health Department.
It is unclear why the owner of The Ardsley conducted the evaluation, but it may be related to the increased attention Legionnaires’ disease has received in New York City over the past month.
“Your cooperation is very important so that the disinfection and flushing can be completed throughout the building,” the memo adds.
The Health Department’s official page on Legionnaires’ Disease has a section that specifically addresses hot water systems.
“When there are multiple people in a neighborhood with Legionnaires’ disease (community cluster), common sources of exposure are cooling towers, hot tubs, and spray fountains,” the Health Department page reads. “At other times, when there are multiple people with Legionnaires’ disease who live in the same building (building cluster), the exposure is typically related to a building’s plumbing system — most often the hot water system. When this happens, a building’s residents can be exposed through water mist when they shower.”
While the bacteria has been detected in the Upper West Side building, there have been no reports of any building or neighborhood residents contracting Legionnaires’ disease.
“Residents can still drink water. They can take baths,” a senior official from the Health Department told West Side Rag. “We do tell them to reduce the risk of steam showers. You should be avoiding mist. Similar to a community cluster outbreak. The same type of risk applies.”
The Ardsley is an Art-Deco building with more than 200 units. The 22-story building was constructed in 1931 and offers a variety of amenities, including a 24-hour doorman. Celebrities such as Barbara Streisand, Ellie Kemper, and David Duchovny have all been tenants of the building.
If you are a resident of the building who begins to feel flu like symptoms, the New York Health Department recommends seeking medical care to get an antibiotic that counteracts the disease.
“Residents who are concerned about their individual risk or who experience symptoms such as fever, cough, shortness of breath, headache, or muscle aches should contact their healthcare provider and advise the provider that Legionella was detected in building water samples,” the memo from The Ardsley to its residents reads.
There is currently an outbreak of Legionnaires’ disease on the Upper East Side, where water-cooling towers at 31 buildings in the neighborhood have tested positive for Legionella. As of Friday evening, there are 54 confirmed cases of Legionnaires’ disease connected to the Upper East Side cluster, according to the city’s Health Department.
In these 31 buildings, unlike at The Ardsley, the cases are not connected to the building’s plumbing system, but instead to the water-cooling towers. While showers are a way, albeit a rare way, that the disease can spread, the Health Department offers these other reminders.
- Legionnaires disease is not contagious.
- You cannot get Legionnaires’ disease by drinking water, cooking, or using air conditioning.
- The bacteria that causes Legionnaires’ disease does not spread through cooled air from air conditioners.
Most people who are exposed to the Legionella bacteria do not get the disease, but you are at an increased risk of contracting it if you are over the age of 50, smoke or vape, have a chronic heart, lung, kidney, or liver disease or diabetes, or a have a weakened immune system, according to the Health Department.
Legionnaires’ is a rare form of pneumonia that is caused by the Legionella bacteria, which grow in warm water and spread in a building’s water system. The disease is not completely uncommon in the city as there are generally between 200 and 700 cases in the five boroughs each year, according to data from the city.
It is more uncommon, though, for so many cases of the disease to be connected to one outbreak, such as what’s happened on the Upper East Side in the past few weeks.
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Coming over from the UES.
Yea, um, no. That’s not how it works.
Why do you think they are in clusters?
Not funny Tim.
Thank you for this article. Very helpful information.
You often see fans of the Disney Channel show “Jessie” taking photos of The Ardsley, which was used for the show’s exterior shots.
It would be good to know what prompted the testing at the Ardsley, since nobody in the building reported contracting the disease. And how many other large UWS building are being tested.
Valuable information that hopefully helps soothe some of the more naturally alarmist among us. Thanks
It soothes you? It makes me think the building is a rare one, that did the testing despite the assumption that the East Side was somehow “contained.”
The information regarding transmission difficulty soothes me. Some seem to think that being in a 50 yard proximity will lead to an unfortunate demise.
The article does not explain why they decided to test the hot water system in that particular building while there were no complaints and residents exhibited no symptoms. Something is clearly missing here.
Many buildings have detectable levels of Legionella in their hot water system. You can’t ‘clean’ a hot water system like you do a cooling tower. It’s controlled by heating the water system high enough to kill the bacteria. My guess is the level was high enough to require action to remediate the situation.
I was a building engneer for 25 years and that’s how we controlled the Legionella issue in every building I worked in.
Maybe I’m stupid, but if heat kills it, how would it have been detected in a hot water system?
I mean, it’s been in the news recently and it might be as simple as they realized it has been a while since the last city inspection and might be worth having it checked. Not everything is conspiracy.
Not everything, but most. Deliberate neglect. Even benign neglect. Cost-cutting measures that don’t benefit the people who will suffer. Etc.
The recent Legionaires outbreak is yet another example of how NYC government fails us. Obviously inspections are not being done and neither Brad Lander or Mark Levine has done anything to audit the agencies responsible. Yet, people will vote them in again and again
The recent Legionnaires outbreak is yet another example about how landlords and big real estate are not doing their jobs.
Do you think every building in NYC should routinely be inspected for Legionnaires’ disease in the water system? It is a rather rare disease. When it is diagnosed, the city immediately begins doing inspections, or more likely contracting for them with outside firms. I wouldn’t want them requiring every building in NYC to routinely check for Legionnaires’ in our water systems – FISPi is quite bad (and expensive) enough!
Brad Lander, btw, was comptroller in the past, out of office for a year and a half, and has now won the Democratic nomination for Congress. What would he have to do with this? Mark Levine is borough president, also not a role that has anything to do with this. If you wanted someone to introduce a new regulation requiring routine testing when there is no reason to think there is any contaminatoin, it would be the City Council we’re talking about, not the former comptroller or the borough president.
But let’s hope they don’t impose that on every building in the city.
Lot of misinformation in your comment. Brad Lander’s term as comptroller ended Jan 1 2026. He has not been “out of office for a year and a half”. It may have seemed that was as he basically stopped showing up for work. Mark Levine is now the comptroller since Jan 1 not the borough President.
Building water systems that use a tank are already required by law to be routinely inspected and tested once a year for all kinds of contaminants including bacteria. Building cooling towers are required to test every 31 days up from 90 for legionella.
It is the job of the comptroller to make sure that city agencies are doing their jobs.
Hope this clears it up for you.
Wealthy co-op boards are, if the theory is correct, choosing to ignore regulatory requirements, and your focus is on…Brad Lander?
BTW, you can look up the recent Ardsley inspection reports online. Their system was last inspected in early August 2025, and passed all checks. Weird how people know so little of the nuts and bolts of city governance.
(Given the news lately, it wouldn’t be at all surprising if the Ardsley had decided to do its annual testing a few weeks early.)
FYI – Brad Lander was never in our district, so not sure why this comment is relevant.
He was the NYC comptroller, the CFO for the ENTIRE city, including us.
Each year these systems and every building water tank is cleaned, inspected and tested for various types of bacteria. It would be a one-line order to add testing for this be done at the same time.
After several pervious outbreaks in the city, he could have pushed for this addition
Lander was Comptroller in the previous administration and we had an outbreak of legionaires in 2025. Auditing the performance of city agencies is one of the jobs of the comptroller as mandated by the city charter. Obviously, Brad was too busy with his performances at immigration court to do his job. This outbreak is not a surprise when inspections and enforcement are not happening.
While it’s true that the comptroller has the power to audit city agencies, the idea that he’s responsible for chasing around after the day-to-day performance of every city employee at every agency is absurd. He’s also not responsible for public health regulations, as Robert suggests, and, if a comptroller just randomly imposed additional ones beyond the existing regulations, people would be screaming about regulatory burden.
You all just don’t like the man because seeing someone with an actual conscience gives you an uneasy feeling in your stomachs.
All buildings should be tested. Why wait til people get sick ? Oh consideration of cost is more important than people’s’ health.
All building water supplies are required to be inspected yearly if they use any type of tank. Cooling towers every 31 days for legionellla if they are in operation.
There are tradeoffs related to the probability of contamination, given contamination the probability of illness, and all the other things to benefit our health or quality of life that we need to spend money on. We shouldn’t automatically assume that all testing is worth the cost. Legionnaires’ disease is quite rare, I’m inclined to suspect that testing all buildings in the city for it on a routine basis is not likely to be a good use of money.
But then I also sometimes wonder whether the fact that in 1979 a young woman was killed by falling masonry is sufficient to warrant the millions and millions that have gone into compliance with Local Law 11 since then. Though, of course, there’s no way to know how many more people might have been killed by falling masonry had we not implemented the FISP program, so it’s kind of impossible to evaluate costs & benefits.
All the buildings in the UWS needs to be tested. But they’ll never do it. They just like to put bandaids on wounds that pop up.
After 5 years-Covid free living in Japan I returned to the UWS for a month last year and promptly got Covid. The CareMD doctor I saw smiled and said “NYC is a giant petri dish”.
Stay safe, New yorkers!
Testing, draining and sanitizing should wait until infections begin. These actions should be done every year prior to the summer. Why do we wait until people get sick.
The city needs to establish a Dept of Quality Control that assures processes are being followed. So many audio street crossing indicators do not work and need to addressed. In this case are health at risk. Come on NY, we can do better.
Hey Gus, congrats on breaking this story! I heard you on WNYC earlier. Nice to be “in the know” here with the Rag.
Resident of the beautiful Ardsley here:
1. Samuel Ramey, the former star bass of The Metropolitan Opera, also used to live here.
2. It’s a good thing to include in the body of an email to shareholders certain precautions, e.g., don’t take a hot shower. This was in a link, but many people don’t press links, either because they are afraid of being hacked, or because they just don’t press links.
We have this every summer in the upper half of Manhattan. Maybe there should be more random inspections or routine cleaning and flushing.
This kind of issue should be non existent if of course most buildings in the city had their properties maintained and managed by a proactive and competent staff that “did the rounds” and looked at potential problems from a proactive standpoint other than reactive. For example in this case, how about you flush the buildings’ water systems systematically , say every spring and fall. Maintain water towers and make sure the hot water systems are heated at the proper temp to combat contamination. Develop the attitude of let’s not wait for something to happen let’s anticipate what can happen and deal with it then so it won’t become a major problem. That’s called a responsible work ethic. Wish my building currently did that as we had one handyman that was amazing and he did work like that. He retired sadly and the building hasn’t been maintained the same way since. Unfortunately that mindset is rare these days if its even there at all anymore. Makes all the difference.