Seems to be a flow problem....

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by DIY, Apr 15, 2008.

  1. DIY

    DIY New Member

    Messages:
    153
    Location:
    Florida
    The water main from the meter by the curb to where it enters the house is double triple checked ,Plumber certified clear aok. Here is what is going on. At the outside hose bib turned all the way open i get a reading of 70-75 water psi. When i turn on the faucet in the bathroom or kitchen or tub,or flush the toilet the psi drops to 20.This happens whether i turn on the hot or cold side of the tub or any of the faucets. If the toilet is flushed it takes nearly 2 minutes to fill back to water level. After that the water psi is back to normal. Could the flow problem be at a defective supply valve at either sink or toilet? I checked those all they seem to work fine going through the open closed procedure a few times. I figure if flow was bad it would perhaps only show up at one faucet or only happen on the hot or cold side...? Where to look next?

    Thanks to all replys!!!
  2. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    Somewhere between where you are measuring the pressure and the city water main there is a restriction that is not allowing enough water volume to pass. This is causing the pressure drop. Where did the plumber measure pressure when he certified the line to be "A" OK?
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,045
    Location:
    Cave Creek, Arizona
    flow

    What do you mean by "double triple checked". Do you mean mechanical devices or just that someone has looked at it several times? You have a restriction in the line, usually a defective pressure regulating valve, but possibly a partially closed or broken supply valve,or a pinched supply line, or .......................
  4. DIY

    DIY New Member

    Messages:
    153
    Location:
    Florida
    flow

    Thanks for the replys Redwood and hj.

    The plumber measured the psi at these 2 locations along the main: At an outside hose bib located @ 3/4 of the length of the main line after the water meter. 2nd location measured was at the shut off valve located just inside the house under a counter top next to the hot water heater. The plumber unhooked the cold line off of the shut off valve that goes into the water heater ,and hooked the psi gauge directly onto the shut off valve. Both places read 70-75psi (actually a little higher reading at the shut off valve location as the plumber told me because it's a direct straight run to the shut off valve,rather than a "T" where the hose bib is located) But when a faucet is turned on or toilet is flushed the psi drops to 20.

    Yes hj i did not get a chance before i sent the message with "double triple checked" aka it was meant to mean things were looked at several times.

    Check this out too. The house next door to me had there entire place re piped main (PVC) (in house has all copper)new valves etc. this was done @ 8 years ago. Right after that it made no change to the psi or flow for that matter as they were and still are experiencing the same problems i have.... The city came out and tested the psi/flow here on there end ,and everything is set and working to where it should be.. Short of replaceing the main ( but it appears all clear) perhaps a start would be replacing all supply valves in the kitchen,bathroom faucets and toilet?

    Thanks to all again!
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,266
    Location:
    New England
    When no water is flowing, the pressure will be the same everywhere in the system...this is true if the size of the pipe is 1/8" or 2'. You won't get much flow out of 1/8", though. As noted, JUST a pressure test is useless...you need a flow test.

    It could be any of the things HJ mentioned. If you have any galvanized pipe in the house or from the street, THAT could be the problem, since if it is old (and it doesn't have to be that old), it can and will corrode, causing a major flow problem.
  6. DIY

    DIY New Member

    Messages:
    153
    Location:
    Florida
    flow

    Ok,since my last message and between work, the city did come back out here. Wow pretty quick for them! They were kind enough and did a video scope of the whole main and the section under the slab they were also able to scope. The video showed no major,no minor blockages bends or kinks in the main. The scope went fairly easy to the other end of main where it goes into the house. This really suprised me as the main is 3/4" galvanized line. They also managed to scope as much water line they could that goes into the house...that all checked ok to. Ok so if i do a flow test it will show the flow is interupted..but where..As mentioned before the house next door got a complete repipe for the exact problem here yet, the repipe solved nothing. Does any flow test pinpoint or tell whereabouts a flow restriction detected might be?

    Thanks once again all!

    p.s. what would the plumbers out there do ,replace etc. if they encountered this on a call?
  7. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    You need to put the gauge on that hose bib near where the water comes in and then run as much water as you can somewhere in the house, such as a bathtub faucet and/or a hose bib on the other side of the house.

    If the pressure drops seriously near the incoming pipe when you are filling the bathtub, then the problem is in the incoming line. If the pressure stays high there when the bathtub is being filled, then the incoming line is OK.

    Then put the pressure gauge on at the hot water faucet at the laundry and run the bathtub hot faucet and the hose bib farthest from the inlet. If the pressure is still high then that supply line is not plugged. If the first test showed little pressure drop on the incoming line and the second test show large pressure drop when measured on laundry line, then you have a pressure loss on the internal lines.
  8. DIY

    DIY New Member

    Messages:
    153
    Location:
    Florida
    flow/psi

    Thanks BobH , The first test resulted in the following:

    First of all this house only has one outside hose bib now in the back. No laundry hoookups either as of yet. Checking the water psi/flow is partly in preperation for that in the next month or 2.

    1. Psi gauge on outside hose bib open it reads 70-75psi. Turn on the cold side of tub faucet psi drops to 5 psi. Hot side of tub faucet open and psi drops to 30-35psi

    2. Psi gauge on outside hose bib open it reads 70-75psi. With cold side of bathroom faucet open psi drops to 50. With hot side of bathroom faucet open psi drops to 55.

    3. Psi gauge on outside hose bib open it reads 70-75psi. With toilet flushed psi drops to 20 psi.


    In lew of no laundry hose bibs at this time where would it be advisable to hook the psi gauge to to check any internal water lines as you suggested?


    All help and suggestions much appreciated!!
  9. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    Is the tee that branches off to the tub faucet near the line to the hose bib where the pressure gauge is located?

    With the gauge on the hose bib (open to gauge but no flow through the hose bib) open the tub cold faucet (where you reported 5 psi at the hose bib) and measure the GPM using a container and timer for seconds. Repeat for the hot water faucet at the tub.

    It would be good if you could put the pressure gauge near where the pipe comes into the house. That would let you determine of the pressure loss is caused by the pipe between street and house, or within the house.
  10. MACPLUMB 777

    MACPLUMB 777 TROJAN WORLDWIDE SALES RP

    Messages:
    679
    Location:
    Houston, Texas, United States
    Water Flow Problem

    IF according to you the house next door has the same problem ? ?
    even after the recent re pipe of the house,
    i would suggest that the problem is with the city water main ! !
    it's not completely out of the question for the city to have problem either
    with their own P.R.V. or collapsed water main, clogged water service ? ? ?
  11. DIY

    DIY New Member

    Messages:
    153
    Location:
    Florida
    flow/psi

    BobNH i would guess from the looks of the distance from the hose bib to where the supply to the shower/tub valve is, is @ 4 to 6'. To measure the GPM at the tub on the hot and cold water sides, not the psi,will check that tomorrow. Do you know what kind of a GPM number i should be looking for?

    Macplumb777 Yep, i did have the city come out and test their end at the street all was said to be ok fine psi/flow and GPM. (posted earlier in this this thread)


    The thank you's are endless...lol
  12. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Messages:
    1,328
    Location:
    Columbus, OH
    I've never heard of a potable water system being cameraed ... that's kind of neat. How did they enter the pressurized main? It had water in it, no? Did they santatize their equipment before inserting it?

    Jason
  13. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,045
    Location:
    Cave Creek, Arizona
    scope?

    That must be one very small camera if it could fit into a 3/4" line especially rusty galvanized. Someone is getting a snow job about that one. You have an obstruction of some kind and a good plumber should be able to determine what and in which area given enough test points. We cannot do it because there are many posibilities that are specific to your situation and we would have to be there and do our own tests. I NEVER trust test data someone else gives me, I want to do it myself.
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