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Thread: Sump Pump loud bouncing noise.

  1. #1

    Default Sump Pump loud bouncing noise.

    When our sump pump in the basement runs and shuts off there is a loud bouncing noise. We tried tp replace the check valve but it still did it. It did not use to make this noise. This is the first winter we have had this sump pump.

  2. #2


    One possibility would be to check how tight and secure is the discharge piping to your wall. Some builder installations have little in the way of secure bracing to minimize any movement of the pipe when the check valve slams shut. Second question, was a new pump installed since last winter? If so, is it a heavier cast iron unit or a lightweight plastic one?

  3. #3


    It a heavier cast iron unit. Our other sump pump quit working and we replace it with this one last summer. We tried to drill a small hole between the pump and check value for air pressure but that didn't do anything. The pipes are secure.

  4. #4


    If you are sure that there are no defects with either your pump or check valve and that there is absolutely NO movement in your discharge pipe, then another suggestion would be to dampen the pipe.

    Get some soft foam insulation or rubber and cut it to encase your discharge pipe. Make sure that there is insulation between the pipe and the wall it is attached to. Secure the insulation with tape, zipties, wire, etc. Also, look at the opening where the discharge pipe exits the house....probably above your sill plate in a joist cavity. Make sure there is no room for movement there either and fill any gaps.

  5. #5


    We do not believe the problem is in the pipes....it is the flap in the check valve. When the pump turns off it "flaps" several times making it sound like a bouncing ball.

  6. #6
    Previous member
    Join Date
    Jul 2005
    Riverview, Fl.


    What pump did you buy? What horsepower? And how many gallons per minute can it pump at your elevation? What check valve do you have?


  7. #7


    If it's the checkvalve, please elaborate on what kind it is and where. Some CV's are junk (ex. plastic Flotec at Home Depot)...replace it with a something like a Zoeller CV that has some has some steel in the flapper assembly.


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