Small leak from disposal drain under kitchen sink

[Bman3]

I recently replaced plumbing in a newly remodeled kitchen. I always hated the brass waste lines draining into a cooper adapter that went into cast iron behind the wall. I found the brass to be the weak link and changing the brass to poly seemed a minimal upgrade. On occasion the sanitary T narrow connection would clog.

Because the new sink mounted under counter and I selected a large Insinkerator disposal I had 1/4 inch drop from the disposal outlet to the wall drain height. I used SCH 40 PVC with a wye from the 1-1/2 copper wall adapter to to the slip joint connectors.

What I’m finding is a very slight water drip on the slip joint connection from the disposal ( in the foreground to the p trap.

What’s the solution to stop the drip? Teflon tape on the slip joint connection?

 

[Reach4]

That red washer is not doing anything.

How does the altitude of the entry into the wall compare to the altitude of the output of the disposal?

Your tilted discharge tube is not usual. I don't know what it would take to raise the altitude of your trap adapter a bit; I don't know what is available to fit the input side of your glued disposal trap. If you had used a slip joint trap, instead of a glued trap, I think it would not have had the stress.

Anyway, I doubt that tape on the slip joint connection would be a positive.

 

[Sponsor]

 

[Bman3]

In the second picture I took the photo with the connection open on the slip joint. The red washer is a tapered Oatey slip joint washer. Fat part of the taper toward the nut. The connector for the P trap in the front is a street 90 from the Wye connected with a two inch length of PVC to the P trap. I could shorten the connection about 1/4 of an inch, but not much more.

The altitude of the entry into the wall is 3/8 of an inch lower than the disposal output. I had to put 3/4 of an inch of plywood on top of the cabinet base to get that height.

So what your saying is the tilt from the discharge tube is causing the leak.