Draining kitchen sink flushes toilet

jandree22August 2, 2010

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.

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.

Any thoughts would be great, thanks!

Thank you for reporting this comment. Undo
brickeyee

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.

    Bookmark   August 3, 2010 at 9:15AM
Thank you for reporting this comment. Undo
jandree22

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.

    Bookmark   August 3, 2010 at 12:58PM
Thank you for reporting this comment. Undo
brickeyee

"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.

    Bookmark   August 3, 2010 at 7:45PM
Sign Up to comment
More Discussions
Waste pipe uneven elbow leak
The gaskets are removed to show the situation in the...
rubyhum
Grohe Ladylux Cafe Touch Faucet
Does anyone have this faucet, and if so, do you like...
sharon_va
Culligan HE vs Kinetico Premier vs Fleck
Hi, After doing some research regarding the above water...
blessedmomof4
Freezeless Hydrant Frozen??
Hi, I have freezeless hydrant that has never given...
den75
Am I the only one bothered by this?
Since Houzz took over, these forums have become a spam-infested...
aliceinwonderland_id
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™