main water pressure question

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You may have a problem between the meter and the house. I had over 90-psi static pressure, which dropped to around thirty with one fixture running. The sixty feet of 3/4-galvanized steel between the meter and the house, had enough chancer on the interior that the friction loss was huge.

Replaced it with pex in a poly sleeve, and the problem was solved.

So, do you have any steel pipe which could be corroded on your system? Or, any other lines that could be pinched or deformed?
 
Where is backflow valve located?
Do you have fire suppression off that service?
Do you know what type of backflow device it is? For example: Reduced Pressure Zone(has a drain)(close to 14 psi pressure loss); Double Check Valve Assembly (no drain)( about 4 to 5 PSI loss).
 
Do you have a water meter? If so have it checked by the water dept. Did this problem just start or has it been going on for
a long time.
 
The city water guy says the pressure is within their limits, though on the very low end. It turns out that all the fixtures are so clogged with corrosion they are blocking the water flow and will have to be replaced. I guess that's why the urinals are the only devices that seem to have decent flow. What a goose chase.... thanks everyone for your thoughtful input!
 
The city water guy says the pressure is within their limits, though on the very low end. It turns out that all the fixtures are so clogged with corrosion they are blocking the water flow and will have to be replaced. I guess that's why the urinals are the only devices that seem to have decent flow. What a goose chase.... thanks everyone for your thoughtful input!
How was "all the fixtures..clogged with corrosion..." determined?

Did the city water guys flow the water for the pressure test? If not, it's not confirming city water pressure while flowing.
 
How was "all the fixtures..clogged with corrosion..." determined?
Did the city water guys flow the water for the pressure test? If not, it's not confirming city water pressure while flowing.

I tested the pressure while the water was flowing (noted above "flush the toilet which is closest to the water meter, it drops to 48-50psi"). Unfortunately, I wasn't there when the city guy came. He stated to the building owner that as long as they supply 40psi it is considered good and it is at 58, or 48 when flowing. Pulling the supply line for a faucet and getting lots of pressure and flow but reconnecting to the fixture and the flow is negligible is how the problem was identified. We'll see as they have a couple guys in replacing all the fixtures today....
 
I tested the pressure while the water was flowing (noted above "flush the toilet which is closest to the water meter, it drops to 48-50psi"). Unfortunately, I wasn't there when the city guy came. He stated to the building owner that as long as they supply 40psi it is considered good and it is at 58, or 48 when flowing. Pulling the supply line for a faucet and getting lots of pressure and flow but reconnecting to the fixture and the flow is negligible is how the problem was identified. We'll see as they have a couple guys in replacing all the fixtures today....
It does, in fact, appear to be your problem, from what you found. For future reference, not knowing the rate of flow when pressure dropped about 10 psi doesn't really determine adequate pressure for sure. As an example, you could be flowing 1 or 2 GPM with a pressure drop like what you got and that would indicate a possible restriction in the service before the meter. The only thing that sounded somewhat positive, in terms of adequate pressure coming in from the meter was your statement, "most of my facility is suffering from low flow except possibly the urinal." Being a urinal, I assume it has a flush valve, which requires a minimum pressure of around 15 psi. But even then, both problems may exist. Marginal or low dynamic(flowing) city water pressure and fixture blockage.
You had mentioned that removing the shower head DID NOT show an improvement in the available flow/pressure.
It sounds like, in the absence of sufficient information to help to more accurately evaluate where problems may or may not exist, I can't be of any help to you.
 
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