I would like to know if there is a minimum requirement for water pressure supplied to an apartment in a high rise in Manhattan.
If so, where can I find written documentation.

I would like to know if there is a minimum requirement for water pressure supplied to an apartment in a high rise in Manhattan.
If so, where can I find written documentation.
What's your PSI in your apartment? This can be checked by a hose bib gage,(see image) attached to a washer hose faqucet. What floor do you live on?
Did you ever have good pressure? Most high raises have booster pump installed about midway up the building. Where's yours? Let me know, Tom

I do not think there is any requirements as per say. . Average pressure in the US is around 35 psi. I know areas here in So.California that have only 20 psi and then you go 30 miles away and pressure is 180 psi.

Highrises present different problem. Water is usually pumped in to a storage tank located up on the roof. Water then falls down by gravity. I worked in the City (Mid-Town and Upper East Side ) for several years and the biggest problem were deteriorating and undersized pipes. Also, sometimes real estate speculators convert regular buildings into condos to maximize their profist. They do nice remodel - but forget about upgrading plumbing system.

What you have is most-likely inadequate volume delivery, not pressure.

What are the symptoms ? Please, let us know, so we can advice. Thanks. Milo

It's actually an apt that we did a renovation in. the new showerbody has a thermostatic pressure balance and conforms with the new restricted flow parameters. And if I remember correctly, the flushometer is a 1.6 flush.
The pressure at the riser is 17 psi +-.
The problem is, prior to our work, her delivery was fine using the old gate valves in the shower and the 3.5 flush.

Your remodel did not change your pressure but you may have caused a restriction that reduces your volume. What type and size valves did you use?

Your remodel did not change your pressure but you may have caused a restriction that reduces your volume. What type and size valves did you use?

We used ball valves at the riser. The branch was 3/4 to the flushometer and 1/2 to the lavatory and shower. Everything was replaced exactly as it was originally.
I did locate a chart in the NYC plumbing code stating that 25 psi is required at a temp controlled showerbody, and 20 at this type of flushometer valve.
I think the pressure/flow has always been inadequate, but the original equipment allowed unrestricted flow so it wasn't apparent.

Truth is that new valves are made with restricted water flow. Also, your shower head has flow restrictor in it. Did you try to remove it and run water w/o the flow restrictor ? Also, some high-end temp-valves, like Hansgrohe, Grohe, Dornbracht, Jade, Axor, KWC, etc. have filter screens inside that may be partially restricted by debris from remodel.

Truth is that new valves are made with restricted water flow. Also, your shower head has flow restrictor in it. Did you try to remove it and run water w/o the flow restrictor ? Also, some high-end temp-valves, like Hansgrohe, Grohe, Dornbracht, Jade, Axor, KWC, etc. have filter screens inside that may be partially restricted by debris from remodel.

I've removed and tested pressure at the shower head, the shower body and the flush valve. There was a bit of flux in the screens. But after cleaning the difference was minor. I changed the diaphragm in the flush valve to a 3.5 and it got much better.
We tested the pressure at the main feed in the basement, calculated the drop due to rise to the 1th floor, and we're getting what we should. So there doesn't appear to be any supplemental booster in line.
I guess my bottom line is, we need to use the restricted flow devices to meet current code. So if there were a minimum psi requirement to residential apartments that is not being met, we could focus on resolving that issue.
I've been doing renovation work in Manhattan for the last 7 years, there is always a noticeable drop with the new fixtures. I'm nearly at the point of reinstalling unrestricted flow devices and ignoring the code requirements.