Dual Check Valve Question

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by jgbfl, Feb 14, 2007.

  1. jgbfl

    jgbfl New Member

    Dec 28, 2006
    I spoke with the plumbing inspector about my final inspections for my new house.
    He informed me that I would need a dual check valve installed between the storage tank and the well head. He would not accept the fact that the submersible pump has a check valve on it.
    My question is, will installing this valve have any adverse effects on how this pump/system performs/operates.

    I have included a few photos to show where I plan to install the valve.
    Thank you in advance.


  2. Rancher

    Rancher Guest

    No it should not affect how your system performs, but just one more thing to go wrong.

    The check valve at the submersible doesn't stop the siphoning of water back down your well if you get a pin hole in the drop pipe, or if that check valve leaks..

    Question, did you plumb into the bottom of your storage tank, or the top where it would never siphon the water back out?


    What is a residential dual check valve (rdc)?
    An rdc is similar to a DC (double check valve) in that it is a mechanical backflow preventer consisting of two independently acting, spring-loaded check valves. However, it usually does not include shutoff valves, may or may not be equipped with test cocks or ports, and is generally less reliable than a DC. An rdc is effective against backpressure backflow and backsiphonage but should be used to isolate only non-health hazards and is intended for use only in water service connections to single-family homes.

    However if you have an air gap, i.e. filling from the top of the tank....

    What is an air gap?
    An air gap is a vertical, physical separation between the end of a water supply outlet and the flood-level rim of a receiving vessel. This separation must be at least twice the diameter of the water supply outlet and never less than one inch. An air gap is considered the maximum protection available against backpressure backflow or backsiphonage but is not always practical and can easily be bypassed.

    Having said that, your inspector is the final athourity.

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  4. jgbfl

    jgbfl New Member

    Dec 28, 2006
    Thanks for the response.
    I have plumbed the tank from the top with an air gap, hence the agitation of the water releases the trapped sulfer. I informed the inspector that I do in fact have an air gap where the water from the house could never be siphoned back into the well.

    He said the code was intended if an irrigation system was installed on the supply. I will eventually design irrigation to run off of this source but I would have installed the check valve at the branch main to the main irrigaion line.
    Oh well I guess I'll just put the valve in.

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