Bad Check Valve? Pressure tank drains during power outage.

Discussion in 'Pumps and Tanks Well Forum & Blog' started by JDM, Apr 18, 2014.

  1. JDM

    JDM New Member

    Messages:
    6
    Location:
    Snohomish County, WA
    We've been in our new house about a year now. We finally had a sustained power outage. When I woke in the morning there was no water pressure. I checked the pressure tank and found it was empty! This has happened twice now. I assume it is the check valve (located a foot or two below ground at the well head). This must be a very slow leak as the pressure sure doesn't drop fast enough for me to see it at the gauge. It took many hours.

    Is this likely to be a bad check valve? (the only other option I can think of is a leaky Pex line to the house...)

    Can check valves be repaired or is it best to replace it?

    I'm not certain but it may be horizontal. Is there a preferred orientation?

    Any plumber types in the Monroe, Washington area on the forum?

    There is certainly a lot of info in the forum and I apologize as I'm sure the answers are here somewhere.........

    Thanks!
    Joe
  2. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,248
    Location:
    Land of Cheese
    If the pump is in the well, it has a check valve in it, which should be the only check valve needed. With that, the leak could be in the drop pipe or the pitless adapter.
  3. JDM

    JDM New Member

    Messages:
    6
    Location:
    Snohomish County, WA
    Good point... The pump is in the well (~180ft). I guess I'll be digging things up to check the valve and the pitless adapter. Thanks! - Joe
  4. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,989
    Location:
    NW Ontario, Canada
    Before you go digging it up for such a slow leak, have you confirmed there is no usage in the house? A leaking toilet flapper or an R/O filter? A softener leaking to drain?

    If you have a reliable shutoff between the tank and the house, try turning it and the pump off to see if you still lose pressure.
  5. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,161
    Location:
    Houston, TX

    Good Advice.


    What is "a sustained power outage" ?

    The pump should fill the tank, after power is restored.

    It was most likely used while the power was off.


    Good Luck.
  6. JDM

    JDM New Member

    Messages:
    6
    Location:
    Snohomish County, WA
    Yes, more great advice. I don't think it was usage in the house as we went to bed just after the power went out. Also, when I got up in the morning I found no pressure so I checked the pressure tank. I could easily rock it indicating it appeared to be completely empty. Let me know if I'm wrong but I didn't think the residual pressure would be sufficient to completely drain the tank through an iron filter and a softener, especially since it is in the crawl space 1 floor down. The pump did fill the tank quickly once I got the generator going.

    Please know that I (and a host of others like me) truly appreciate the time y'all spend on the forum to answer our rookie questions! Thanks!
  7. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,989
    Location:
    NW Ontario, Canada
    The precharge pressure above the bladder would completely empty the tank, even it the water had to go up a floor or more.
  8. JDM

    JDM New Member

    Messages:
    6
    Location:
    Snohomish County, WA
    I didn't anticipate that. Looks like I'll check both sides of the system before I start digging holes! Our filter & softener have Fleck 7000 SXT valves. Maybe they operate when the power is out and flushed one of the tanks? One of them has a flow indicator. That will be my first check.

    THANKS!!
  9. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,161
    Location:
    Houston, TX

    I think the valve will stay in whatever position it was when the power fails.

    A leaky Toilet valve can use a lot of water in the long run also.


    Good Luck
  10. Reach4

    Reach4 Active Member

    Messages:
    2,264
    Location:
    IL
    I would turn off power to the pump, and monitor how quickly pressure drops with no known water consumption. See if it takes 20 minutes or 6 hours to lose pressure. Note how big your pressure tank is.

    Also, consider shutting the valves at the toilets during this test.
  11. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,248
    Location:
    Land of Cheese
    You should have one main shut off after the tank. Closing that would isolate whether the leak is inside or outside.
  12. jimmy klotz

    jimmy klotz plumber, electrician, carpenter

    Messages:
    2
    you should isolate the leak first shutting off the main at the tank is a great way to start and if the tank still drains, change the check valve at top.. i highly doubt a leak in the house because you would notice the pump running every so often without any water being ran..
  13. valveman

    valveman Moderator Staff Member

    Messages:
    4,468
    Location:
    Lubbock, Texas
    I don't recommend a second check valve anywhere in the system, and in many states it is illegal. A check up top may stop the tank from leaking back, but if the check down on the pump is leaking, you will either start getting air in the lines or it will cause a loud water hammer "pop" when the pump starts.
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