bad drop in water pressure when more than one spigot/appliance is turned on.

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by bigchuck80, Oct 11, 2013.

  1. bigchuck80

    bigchuck80 New Member

    Messages:
    5
    Location:
    ohio
    First of all I am a NOVICE. Please be patient and simple with me. I am also a Fed worker who is furloughed, that is why I can't pay for a plumber at this time. Anyway, I had a water main line break a month ago and the line was replaced (plastic). Shortly after the repair, I have had a problem with water pressure or volume. The pressure to the meter from the street is 75lbs, which is good, and also tested on a spigot after the meter, also at 75lbs. If you turn on any spigot in the house, the water flow seems to be pretty good, as long as it is the only thing on, but as soon as a second spigot or water source is turned on, the pressure drops to almost nothing (a trickle). I have checked all of the shut off valves and they appear to be on. The plumber who repaired the line, came back and flushed the meter, but then scratched his head, said he had to research something, and he would call me back the next day. 4 days later he still hasn't returned a call. Any simple things that a novice like myself could check for? Also I don't have a PRV or an expansion tank. House was build mid 70's. Thank you.
    Last edited: Oct 11, 2013
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,423
    Location:
    Bothell, Washington
    First, check to see how much flow is coming out of the outside faucets. You should be able to run both of them very well.
    75 PSI is very good pressure, and a mid 70's home often used 1" block poly pipe with insert fittings and hoseclamps on the water line.

    If the outside faucets run well, check the aerators on the faucet and clean them. Shower heads may have also gotten clogged.
    The tub should run very well. Normally outside faucets and tubs work well since they don't have screens.

    I would hate to think that rocks got in the line and started clogging pipes inside where the fittings reduced.

    Sad to hear about your job. Those job layoffs will be affecting the rest of us too.
    Last edited: Oct 11, 2013
  3. bigchuck80

    bigchuck80 New Member

    Messages:
    5
    Location:
    ohio
    thanks about the job. Even when I had the water break, all my appliances and pressure was good. I only have one outside spigot, and that is the one that had the 75lbs of pressure, until I turned on the washing machine, and the pressure on the spigot went to almost zero. I did clean the aerators on everything but the shower head. I should do the shower head, because the shower seems to be the worst.
  4. Reach4

    Reach4 Well-Known Member

    Messages:
    2,819
    Location:
    IL
    When you turn on those two faucets, what does that pressure gauge read? If it is 60 PSI or more, the problem would be after the gauge. It the pressure is lower, try reading the pressure closer to the street with those two faucets open.

    Do you have a filter or water softener in line?
  5. bigchuck80

    bigchuck80 New Member

    Messages:
    5
    Location:
    ohio
    no filter or softener. What two faucets? The plumber only had the guage on the hose bib inside of the garage. It read 75. Once we turned on another water source (which was the washing machine), the guage went all the way close to zero.
  6. Terry

    Terry Administrator Staff Member

    Messages:
    15,423
    Location:
    Bothell, Washington
    You may need to back flush the house if something got past the repair.
    You have checked to see if the main valve is opened all the way?
  7. Reach4

    Reach4 Well-Known Member

    Messages:
    2,819
    Location:
    IL
    You said "If you turn on any spigot in the house, the water flow seems to be pretty good, as long as it is the only thing on, but as soon as a second spigot or water source is turned on, the pressure drops to almost nothing (a trickle)."

    Turn on whatever makes the pressure at the faucet/spigot/fixture drop to almost nothing, and measure the pressure as close to the meter as you can. That will tell you which side of the pressure gauge the restriction is.
  8. bigchuck80

    bigchuck80 New Member

    Messages:
    5
    Location:
    ohio
    the main shut off valve is open all the way, or it appears to, unless the valve is malfunctioning. Can I back flush the house, or is that something that a plumber needs to do?
  9. bigchuck80

    bigchuck80 New Member

    Messages:
    5
    Location:
    ohio
    okay, got you. The plumber had the gauge, so I will have to pick one up tomorrow at Home Depot. Thanks reach.
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,272
    Location:
    Cave Creek, Arizona
    You describe a malfunctioning pressure regulating valve although you do not say if you have one, otherwise it is a valve that is almost completely closed.
  11. dj2

    dj2 Member

    Messages:
    437
    Location:
    California
    He said he didn't have a PRV.
    If it's a valve that's almost closed, why is the pressure good when only one faucet is on?
    That leaves the possibility of rocks/dirt in the lines.
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,333
    Location:
    New England
    Pressure doesn't drop until you exceed the capacity of the line, and a restriction of any kind could allow one faucet to run 'fine' and things to go to hell when additional flow was called for.
  13. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,272
    Location:
    Cave Creek, Arizona
    HE may not THINK he has one, but the symptoms say he may have one. THere is no way pressure could drop "to almost zero" if it were not a bad valve or PRV, or a clogged meter with fish in it.
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