Return to the Plumbing Forum | Post a Follow-Up

 o
Draining kitchen sink flushes toilet

Posted by jandree22 (My Page) on
Mon, Aug 2, 10 at 20:21

Since we moved into our house, a rapidly draining kitchen sink flushed our toilet. Sometimes the tub would do the same behavior, but not with the same consistency. I suspected a clog in the sewer vent, but after attempts to unclog, no luck... vent is wide open and still happens.

I think I figured out what's going on but not quite sure what to do about it. I've attached an image of my plumbing lines into the main sewer line in the basement. I'm speculating that the rapidly draining kitchen sink is coming down the black line so rapidly, it's shooting straight across horizontally to the white line and interfering with the flow of vent air down the main sewer line. As a result, the falling water is vaccuuming the toilet.

Photobucket

The solution that comes to mind is relocate the entrance of the black kitchen sink/tub line lower, or have it enter the sewage line at a 45* vs laterally. As shown below, I have an untapped entrance to the line further down adjacent to the slop sink.

Photobucket

Any thoughts would be great, thanks!


Follow-Up Postings:

 o
RE: Draining kitchen sink flushes toilet

Sounds like someone left out some vents or the sink vent and tub vent are clogged.

The kitchen sink needs a separate vent from the one in the basement.


 o
RE: Draining kitchen sink flushes toilet

Ah I see. Thanks for that info. I don't know for certain that it's not connected to the main vent up to the roof... just didn't think to check. Will take a closer look tonight.


 o
RE: Draining kitchen sink flushes toilet

"Maybe the plumbing wasn't done professionally."

With joints that appear to be between ABS (black) and PVC (white) it is very doubtful it was done by a plumber, and probably never inspected.

There is no approved cement for joining ABS and PVC.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Plumbing Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here