My home has a sump pump running to a floor drain. While no longer strictly legal in my city, this arrangement has been in place for many years and there isn't a convenient way to get the water outside. The sump doesn't run enough to warrant grave concerns.

The drain is a bit unique, though. It has a 1-1/2" opening all the way up, without the usual collection bowl. It looks similar to this. The sump drain line nearly fills it by itself. I'm not sure what's below the surface of the opening or the concrete slab.

I'd like to securely attach the sump drain and softener discharge lines to the floor drain, while still allowing the floor-level furnace condensate line (which requires an air gap) to drain effectively.

The furnace condensate line does not have a pump. It relies on gravity alone.

Is this feasible? How would you do it?

  • 1
    Softener probably needs to have an air gap on it's discharge line as well.
    – Michael Karas
    Jan 28, 2017 at 17:06
  • why don't you just discharge all of these to the sewer line? one-way valves will prevent them from cross-contaminating.
    – aaron
    Mar 3, 2017 at 21:08
  • @aaron, see my mention of required air gaps. They already do, but they're just jammed in the drain hole. I'd like something more secure and professional.
    – isherwood
    Mar 3, 2017 at 21:11
  • @isherwood - sorry, i misunderstood, thinking that your floor drain was to a dry well or something, not municipal sewer.
    – aaron
    Mar 6, 2017 at 13:13

1 Answer 1


enter image description hereIs it possible to run the softener hose and furnace hose over to the sump pump? I am assuming you have a furnace distillate pup already.

If it is, perhaps you can discharge them there into the sump pump pipe itself, or BETTER snake another pipe down inside that pipe to the drain.

You may have to get creative drilling a hole into the end cap so the smaller pipe is a tight fit and glue it together so it is water tight.

You do not have to go all the way with the concentric pipe though if there is a decent slope on the existing pipe, but since the outlet is so close to the top of the floor drain, I doubt there is.

  • I think you might be onto something there, with the concentric pipe idea. How did you picture the smaller pipe sealing against the end cap?
    – isherwood
    Mar 4, 2017 at 15:51
  • I though about backflow valve too, but not sure you would get enough pressure from the piddle from the others to open it. With the arrangement shown the sump pump would actually draw water out of the other pipe by venture effect... provided the floor drain is not backing up... in which case the water from the hoses is the least of your problem.
    – Trevor_G
    Mar 4, 2017 at 15:52
  • Sorry, I reread and edited. My sump pump is typical and the drain pipe is flexible 1-1/4".
    – isherwood
    Mar 4, 2017 at 15:52
  • I see you've addressed the end cap seal issue, too. My eyes jumped over that paragraph.
    – isherwood
    Mar 4, 2017 at 15:53
  • 1
    BTW: The nice thing about doing what you are thinking of is it keeps the trap in that floor drain filled. They usually dry out over time... then u get that awful sewer smell.
    – Trevor_G
    Mar 4, 2017 at 15:58

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