> New York City’s water (including drinking water) is unfiltered, making it the largest unfiltered water system in the country. Were New York to begin filtering its water, it would cost the city approximately 1 million dollars per day to operate the filtration plant.

They have hundreds of sampling stations to check daily.

https://www.nytimes.com/2025/05/01/nyregion/nyc-tap-water-qu...

This causes some issues for observant Jews, because the water technically might not be kosher.

https://oukosher.org/blog/consumer-news/nyc-water/

https://www.nytimes.com/2004/11/07/nyregion/the-waters-fine-...

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andrewflnr 4 hours ago | parent | next [-]

Ok, but unfiltered does not imply untreated. Maybe that's where they got the idea, though.

	▲	devilbunny 3 hours ago \| parent [-]
		It is, indeed. I'd edit the post but... too late.

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valarauko 3 hours ago | parent | prev | next [-]

It's largely unfiltered, but it is still treated for disinfection. Chlorination and UV is standard for NYC water, and its fluoridated as well.

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markdown an hour ago | parent | prev [-]

Treatment is usually just the addition of chlorine and in some countries, fluoride.

Filtration isn't common.