Water comes up other sink when disposal is on

[vlbridges]

We have been battling this problem for years now. Both kitchen sink sides drain freely. But...if there is water in the disposal side and the disposal is turned on, there is bubbling and gurgling on the disposal side and water comes up into the other sink. Any ideas?

[jimbo]

It the drains are really ok, then to some extent this may just be the nature of your installation. The disposer acts as sort of a pump, and as it send the water out, that water will look for the path of least resistance, and will often split between going down the drain and going across to the other sink.

If you could post a picture of the piping under the sink, this could be made clear.

[SewerRatz]

We have been battling this problem for years now. Both kitchen sink sides drain freely. But...if there is water in the disposal side and the disposal is turned on, there is bubbling and gurgling on the disposal side and water comes up into the other sink. Any ideas?

Do a small test, fill up the side without the disposal. Fill it all the way up. Then let it drain and observe what happens on the disposal side. If it backs up into the other side while it is draining then there is a partial blockage.

See most people just run the water in both sides and it will drain just fine, but when you fill a side up and let the water go, you are getting a flow rate greater than what the faucet can supply and it will help you diagnose the issue. Now if it does not back up when you drain that side of the sink. The problem is in how its piped under the sink. Then a picture will be a great help.

[vlbridges]

Do a small test, fill up the side without the disposal. Fill it all the way up. Then let it drain and observe what happens on the disposal side. If it backs up into the other side while it is draining then there is a partial blockage.

See most people just run the water in both sides and it will drain just fine, but when you fill a side up and let the water go, you are getting a flow rate greater than what the faucet can supply and it will help you diagnose the issue. Now if it does not back up when you drain that side of the sink. The problem is in how its piped under the sink. Then a picture will be a great help.

Water comes to the top of the disposal side when a full sink is released from non-disposal side. No gurgling and bubbling. I'm including a photo of the plumbing, but I suspect our 34-year old pipes need a good goosing! :-)

It appears I do not know how to include a photo. sorry.

[vlbridges]

Here we go. By Golly, I think I've got it! :-)

[SewerRatz]

Well yes you have a slow drain, a good power rodding will fix that, then second you need to repipe under your sink. that corrugated pipe needs to go, Also they make a disposal kit for end waste discharge that will get rid of the down turned pipe. Below are some pictures. The tee should have a baffle in it as well.

[SewerRatz]

If you are in Illinois you are not allowed to use a single trap for both sides of the the sink and are not allowed to discharge the dishwasher into the garbage disposal. If you are in Illinois let me know and I will post pics on how it should be installed to meet Illinois code.