Overflow Tank for Toilet

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by sfchap, May 29, 2008.

  1. sfchap

    sfchap New Member

    Messages:
    2
    We are installing a toilet in our basement and the drain pipe has a very small incline to the outside city sewer. Hence as per city regulations, we need to install a backflow valve to prevent he flow back into the house in case of city sewer flooding. All of that makes sense to me.

    Now here is my problem - the city is also asking us to install a relief valve and an overflow tank with an alarm. The reason? They are concerned that if some one flushes the toilet in the unlikely event of city sewer flooding, there is a risk (however small) that the sewage will flow back into the house (not good!). Unfortunately the overflow tank with a built-in alarm is pretty expensive ($700-800).

    Question - Does anyone know of a cheaper but equally effective solution? I should add that installing an overflow pipe to the outside of the house is not a feasible solution.

    Thanks in advance
  2. hj

    hj Moderator & Master Plumber Staff Member

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    26,540
    Location:
    Cave Creek, Arizona
    tank

    Now here is my problem - the city is also asking us to install a relief valve and an overflow tank with an alarm. The reason? They are concerned that if some one flushes the toilet in the unlikely event of city sewer flooding, there is a risk (however small) that the sewage will flow back into the house (not good!). Unfortunately the overflow tank with a built-in alarm is pretty expensive ($700-800).

    It depends on what they mean by an overflow tank. If it is a standard ejector pump arranged so that only excess water goes into it, (and in that case you don't really need an alarm), then it is a good idea because the pump will be able to pump the water out even with the sewer in a flooded condition. At one time, and maybe still today, there were companies that made a combination backwater valve/pump system all in one, and they worked quite well to keep the house functional even when the city sewer had a problem. The advantage of a system such as this is that it also prevents flooding if something is stuck in the backwater valve and is allowing seepage or flow back into the house.
  3. sfchap

    sfchap New Member

    Messages:
    2
    Overflow Tank / Ejector Pump

    I am not sure what the correct name for the "overflow tank" is. Its purpose is to catch the excess sewage (in case of flooding) and pump it out. I understand that some of these have built-in alarm systems so that one knows that there is a blockage. Perhaps it is the same as an ejector pump?! If so, are there known / good brands for these?
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    21,950
    Location:
    New England
    ANything that exits below the sewer line needs a pump to get it into the sewer where gravity can take over. Search on sewage ejector pits and pumps. Installation typically includes a check-valve so you don't have to pump the stuff twice , or continuously. As a side benefit, it blocks any flow from the sewer back into the house (at least while it isn't leaking, which does happen).
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