Water Pressure Problem

Plumbing Forums

Help Support Plumbing Forums:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

dts

New Member
Joined
Apr 28, 2024
Messages
3
Reaction score
0
Location
Pittsburgh, PA
About 8 months ago I purchased a house (2 stories plus basement) built in the early 1990's with a (functioning) pressure reducing valve. Water pressure coming into the house is about 110 psi and the PRV is set to about 60 psi. Over the past few weeks, I have noticed poor water pressure in our 2nd floor master shower. It is a tub shower combo and the pressure seems so low you can not even get the tub spout diverter to hold to take a shower. Pressure everywhere else "seemed" to be normal, but if more than one fixture is running (i.e. washer and sink), the flow out of the sink is so low you can barely wash your hands.

I ran some tests and with a pressure gauge I confirmed the pressure at (2) 1st floor hose bibs, a 1st floor laundry tub, and a basement level garage hose bid are all at 60 psi. I further noticed that when turning on the hose (if nothing else is running in the house), water "shoots" out of the nozzle as it should, and within seconds the flow slows down significantly (like there was a buildup of water and pressure and once released the flow goes back to the new normal). Once you shut the water off, the pressure builds back up to 60 psi as it should.

Any ideas what this could be? At first I thought it was isolated to the master shower and issue with the valve, but it is appearing everywhere. We don't have particularly hard water- at least not noticeably. I took a some aerators off at sinks and there was no considerable buildup of debris. I could adjust the PRV, but with the pressure appearing adequate, I don't think this will help and just put more pressure on the pipes.

Thanks!
 
a main valve that is not fully open. Constricted water flow causes your issue.
 
a main valve that is not fully open. Constricted water flow causes your issue.
Thank you for the response and feedback. I just checked and the main valve is fully open and this does not appear to be the cause.
 
Replace the PRV
I am open to potentially doing this, but with the pressure after the PRV 60psi and steady, I am not sure how this could be the problem. Any ideas on how a bad PRV could cause a pressure drop once water is running (but not before)?
 
I am open to potentially doing this, but with the pressure after the PRV 60psi and steady, I am not sure how this could be the problem. Any ideas on how a bad PRV could cause a pressure drop once water is running (but not before)?
It can be the source of restriction.

Pressure under no flow might be fine. But the flow is restricted when water is used through the prv.

That’s where I’d start. I’m not saying it can’t be anything else……
 
I had a toilet with a very slow refill rate. Found a pebble before the wall valve restricting the flow. We had a water main repair down the street and a fair amount of sediment ended up in all our plumbing restricting flow. It is now fully cleaned out and things are back to normal.

Steven
 
The screen or strainer of the PRV is most likely clogged. That is why we are recommending replacing the PRV.
 
Back
Top