On Pins and Needles - Checkvalve Operations - Hurricane Sandy

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by chefwong, Oct 27, 2012.

  1. chefwong

    chefwong Member

    Jun 14, 2006
    District of Columbia
    Gent's -

    Got flooded last year with Irene....we just finished renovation around August of this year !

    The sewar system could not catch up - so it just all started coming out from the lowest part of the house.
    Got a checkvalve installed. In hindsight, I should have also have had a ballvalve installed Right Behind it.

    Fast forward to upcoming Sandy.
    The premise of the checkvalve is that as water leaves my premise, it pushes the flap open....and let's whatever go past the door.
    To be thoroughly protected, am I NOT SUPPOSED to use any *water-sewar* in order to prevent any water from coming in, should there be backflow of water in the sewer pipe.

    OR, let's just say the kids flush the toilet and there is backflow of water pressure against the door trap.
    Will the door just not open due to the greater pressure against it - In Essence, keeping me protected *aside from the buildup* behind the door.

    Or is it plausiable that if it's not that much pressure, there may be a chance the door will open, and then *remain open* due to water pressure.

    I have not thought out all the options as I'm busy buttoning up the house.
    Last edited: Oct 27, 2012
  2. kreemoweet

    kreemoweet In the Trades

    Sep 7, 2009
    Seattle. WA
    It doesn't matter. If the sewer line backs up to the check valve, anything you send down the house drains is not going anywhere,
    except back up the drainpipe if there's no outlet at the lower level.
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  4. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona
    If the water level on the house side of the check valve is greater than the city side, it will open to equalize the two sides and then close again, but that is VERY UNLIKELY to ever happen. IF anything, such as a Q-tip or popsicle stick or wad of paper, gets caught in the valve's seal/seat you will flood, it will just take longer for it to happen.
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