[devilbunny]

I know NYC doesn't treat their water at all, but LA doesn't either?

My city runs on surface water, so we have treatment and then pump to storage tanks. You would have to be out for quite a while to run the city out of water, though - the tanks are large.

[kenhwang]

LA definitely treats the water. Both the surface water before consumption (I'd be surprised if any city doesn't do this) and the wastewater, for reclamation for nonportable use like irrigation, and for recycling back into the general clean water supply.

The aqueduct water is specifically purified by the Los Angeles Aqueduct Filtration Plant. That plant is gravity fed, but it doesn't operate without power.

LA just has the advantage of having mountains in the city, so it's cheaper building more elevated water storage so the capacity lasts longer during power interruptions (which are also not as common or extended as they are in the east). They will still eventually run out if they're not replenished by powered pumps.

[simtel20]

Where did you get that idea about NYC water being untreated? NYC treats its water. Chlorine is added if and when needed. Testing stations exist to evaluate water quality all around the boroughs, etc.

You can't have a city of millions of people and have the water be potable from the tap without testing and treatment

[ceejayoz]

https://www.nycfoodpolicy.org/10-facts-you-may-not-know-abou...

> 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-...

[andrewflnr]

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

[devilbunny]

It is, indeed. I'd edit the post but... too late.

[valarauko]

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

[markdown]

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

Filtration isn't common.

[devilbunny]

Settlement, however, is fairly standard in surface supply.

[mikestew]

I know NYC doesn't treat their water at all…

EDIT: I'm a dork an grabbed the wrong URL. Changed URL to a PDF for lack of better.

A major metro doesn’t treat its tap water? Where on earth did you get that crazy idea?

<old URL deleted>

https://www.nyc.gov/assets/dep/downloads/pdf/water/drinking-...

I'll save some digging: "Even without filtration, the water is carefully treated to reduce the risk of harmful microorganisms."

[johngunderman]

You linked to wastewater treatment, not drinking water. Wastewater is definitely treated in NYC.

Tap water is treated (UV and chloride disinfecting), but is largely not filtered: https://en.wikipedia.org/wiki/New_York_City_water_supply_sys...

[jmalicki]

He was talking about the drinking water that comes from the faucet, not the sewage.

The untreated NYC water has tiny crustaceans in it, which make it not Kosher, which is why thee bagels from a Jewish deli in NYC are so good. Go figure.

https://newsfeed.time.com/2010/08/31/drink-up-nyc-meet-the-t...

[markdown]

There's no way the water is untreated. Like just about everywhere else on earth, they will add chlorine when necessary.

[mikestew]

Thanks for the correction, I should have looked harder at that page before posting. I've since corrected.