Installed a new single tub kitchen sink and now my drain line backs water into the sink...

[BradOSU99]

Hello all. I'm probably going to hire a plumber, but thought I'd give this a go in case this is actually a really easy solution.

I went from a double tub sink to a single in my kitchen. At the same time, I installed a new dishwasher, new garbage disposal, new plumbing under the sink, and an R/O. Install was pretty simple, but since doing it, I noticed that my drain fills and starts filling into the sink. Turning on the garbage disposal will briefly clear the drain and improve it, but I can still see and hear the water come back up into the disposal. I know for sure there is not a clog. The drain line has a p trap like it should and the plumbing slopes away from the drain as it should.

I believe my problem is an air venting issue. I think the double sink that was there before maybe provided enough venting that this wasn't a problem before, but now it is. Am I right? What else could be the issue if I'm wrong?

 

[Geofd]

You need to show pics of under the your sink take them so they are not to close

 

[Jeff Handy]

Yes, pics needed, hopefully you can just add an air admittance valve to the trap arm.

 

[BradOSU99]

Thank you both for responding. I decided I was in over my head on this one and had two separate plumbers come out to my house yesterday. Each independently confirmed it was in fact a clog further down the line (but before the clean out) and discovered that the riser to the kitchen sink is busted to some degree. It was leaking. I have a 100 year old craftsman home and the plumbing was updated within the last 20 years, but they didn't update the risers. So I still have some small pieces of galvanized in my house. Anyway, I got two separate quotes. One quote to fix plus repair stucco was $1975 and one was about $1500. On top of the $1500 being cheaper, that plumber really seemed much more knowledgeable and was successful at least removing the clog, so we are going with him. It's getting fixed on Friday.

You got a really great forum here! I'll be back I'm sure. This isn't going to be the last problem I have in this old house! lol