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Thread: Well is losing prime...

  1. #1

    Default Well is losing prime...

    Hi folks.

    My deep water well keeps losing prime. I'm thinking two possible causes here. When I leave a tap on and prime the well, I get pressure up to a point, then it goes VERY low... then cycles back up. Sometimes, it will lose prime completely.

    I'm thinking either 1) bad pressure tank or 2) bad check valve down at the end of my lines. Now, replacing the pressure tank is the easier (but costlier) of the two. Should I try that first to see if it fixes the problem, or just go ahead and do both?

    Thanks for any help you can give.

  2. #2
    Previous member
    Join Date
    Jul 2005
    Riverview, Fl.


    The pressure tank does nothing to make or lose pressure, the pump does that.

    Tell us what kind of pump, tank and well you have. And the specs on the well.


  3. #3


    To be honest, I don't know anything about it. It's at my Grandparents old house. They've passed on, and my mother is living there now.

    Tank looks to be 30-40 gallon size and hasn't been replaced in who knows how long. Same with the pump itself. If I remember correctly, the well goes down about 120 feet or so. Again, I don't have the specs on it. How would I go about finding out, short of dropping a weighted string down it?

  4. #4


    Contact your state, most if not all states register the water wells.


  5. #5
    That's all folks! Gary Slusser's Avatar
    Join Date
    Aug 2004
    Wherever I park the motorhome.


    As Bob said, the tank has nothing to do with the problem. Wells don't lose prime, jet pumps lose prime. They do that because of a leak allowing water in the pressure tank and pump to run back down the well. The primary cause of a loss of prime is a leaking foot valve on the end of the drop pipe in the well. That applies to both shallow single line and two line deep well jet pumps. Another potential leak area is in the drop pipe or pipe from the well to the house.
    Gary Slusser Retired (= out of business)
    Click Here to learn how to correctly size or program a water softener.
    CAUTION, as of Nov 12 2013 all YouTube videos showing how to rebuild a Clack valve have an error in them that can cause damage.

  6. #6


    Turned out to be bad contacts on the pressure switch. Well/pump now working fine, thanks for the suggestions!


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