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sewage tank question

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  • sewage tank question

    I live in Ottawa, Ontario.

    The following rough-in (refer to attached diagram) passed inspection in 1994 and consists of the toilet drain, sink drain (connected to toilet drain inside the basement concrete floor) and wet vent (sink drain serves also as vent pipe which is connected to the main vent pipe in the attic). The drain pipe serving the toilet and sink goes to a sewage tank.
    Note that although the picture shows the toilet and the sink, these are not present. Also the drain between the sink and toilet is not shown (I’m not sure how it’s connected underneath the concrete floor).

    I would like to add a shower which was not part of the rough-in. This will require breaking the cement and adding a pipe with ‘P’ trap.

    Can I bring the pipe directly from the shower to the sewage tank (I will need to drill a hole on the side of the tank, connect and seal the pipe around it). If so, do I need a vent since the pipe length will be only ~25" between both ‘open-air’ ends.

    Or, do I need to connect it to the existing drain (assuming that no more than one drain can go to the tank) ?

    Thanks, Guillaume
    Attached Files

  • #2
    Re: sewage tank question

    If it were me, I would T off the sewer already there from the W/C and not put anymore holes in the tank then I had to. I think you should call a plumber if you have to ask how it should be done

    Why do you have a Sewage Tank in your house if you have a septic line going out side?
    I would never have a sewage tank in a house or within 50` of a house.

    Is this a lift station or something?

    Last edited by All Clear Sewer; 08-15-2007, 09:49 AM.


    • #3
      Re: sewage tank question

      Im guessing this is basement bathroom and his sewage "tank" is a sewage sump pump. You will need to add a vent for the shower no matter which way you tie it into the sewage tank. You should take off the TY for the vent inside the wall behind your shower, whichever wall your waterlines and shower valve arent going in. This will enable you to either tie it into the existing vent for t he toilet and sink, or tie it into the vent in your attic (depending on what type of ceiling is in the bathroom, you may be able to access the existing vent) I would use 2" for the drain and 11/2" for the vent. Its more than minimum code requires but showers are very succeptable to plugging. Very nice drawing by the way
      West Trail Mechanical Ltd
      Service. Commitment. Expertise.


      • #4
        Re: sewage tank question

        Thanks for the answers gents,

        Yes, this is for a basement bathroom and the existing sewage tank (~26" dia. x 3' deep) is for a future lift station (there's no sewage pump yet). The actual septic tank is outside the house but higher than the basement.
        Note that everything is roughed-in i.e. there's no walls yet, no ceiling, therefore the existing vent from 'sink-toilet' is easily accessible.

        If I connect the short 25" drain pipe from the shower directly to the sewage tank (note that using this method, there will be no other pipes connected to it), then I'm not sure why I would need a vent through such a short pipe, when both extremities are open to air on a 25" distance.

        However, if by code I do need to connect to the main drain already connected to the sewage tank (such as what "All Clear Sewer" has drawn on his response), then I understand the need of venting to prevent "siphon" problems.

        Bye the way, how do you include drawings in-line instead of an attachment ?

        Thanks, Guillaume


        • #5
          Re: sewage tank question

          You have to have a host to host the picture then you get the properties and past em in this bracket [ img] properties pasted here [ /img]

          Shower drains and tub drains always need a vent to keep things flowing good. There is a lot of hair and soap that will hang up if the line doesn't flow properly. And "YES" if you did go to the existing sewer line ((With-out Venting)) it would also have a chance to siphon the seal out of the trap but I feel it`s better to hook up to an existing line then punch another hole in a lift tank. Just My $.02

          I`d Vent it up the wall and hook up the waste line already there.
          Last edited by All Clear Sewer; 08-16-2007, 01:40 PM.