New York City’s been in the grips of some unforgiving heat and humidity this summer. One of the top tips for staying healthy during such severe weather (and always) is to stay hydrated by drinking a lot of water. And the city extended hours at many of its public pools to give folks as much time as possible to cool off. But how safe is all that water you’re drinking from the tap? And with all those people crowding those huge pools, are you just jumping into a giant petri dish? We talked to Dr. Philip Landrigan, an expert in environmental medicine and public health at Mount Sinai Health System, about the safety of our water.

So, how is New York City’s drinking water?

Some of the best in the world. One of the great breakthroughs in the history of New York City that just changed the quality of life forever, was the construction of the Croton Aqueduct, which brought in clean water from upstate. Prior to that time, New York was regularly, like every five years, was afflicted by massive epidemics of cholera and other infectious diseases that are transmitted by water. Since that time, those epidemics have ceased to exist.

That is great to know. So it’s tested regulary?

Yeah. Now with all of that said … where things can get a little dicey is in the last few feet as the water comes into a person’s home or apartment building, because sometimes in these private dwellings there are old lead pipes … first thing in the morning they may release a little bit of rust, and so on.

Is it a cause for concern to see a bit of rust come out of the tap?

No, it really isn’t. Just run the water until it runs nice and clear. The water has been sitting overnight in contact with the pipes so the water has been sitting in one place overnight.

Let’s talk about NYC’s public pools. How safe is the water in our pools generally?

It depends first of all on the source of the water. My understanding is that most of the pools use New York City water, so the source is therefore extremely good. The second factor is how well the pool is maintained. That means that the filters have to be changed regularly. It means that the various chemicals have to be added. The staff just have to be meticulous. That’s pool by pool.

Is there anything that people who are public pools can do to contribute to the cleanliness and safety of the water?

Everybody who uses a public pool should respect the fact that they’re sharing the water with their neighbors, they should take a shower and use the bathroom before they go to the pool … And certainly not use the pool as a place to relieve themselves. That’s all sort of basic and crude, but it’s worth saying. 

You have medical questions? We have answers. Metro is teaming up with the experts at the esteemed Mount Sinai Health System to provide answers to your most pressing medical concerns. Send us an email at We’ll select one question and publish an answer every other week.