Sink Plumbing – How to Fix Leaking Drain Joint in Reconstructed Pipes Under New Kitchen Sink

absleaksink

We recently installed a new countertop and kitchen sink (which is built into the island). The sink is 2 inches deeper than the old sink, so we had to redo the plumbing to make everything fit. We used ABS pipes, a new out of package p-trap and ABS cement. Currently we have ONE joint that will not stop leaking. It is the joint right off of the disposal (see picture).

Things we have tried after initial installation:

  1. New /different pipe
  2. New / different washer (right now we have a Polyethylene washer designed for a slip nut)
  3. Teflon putty (TFE paste)

At first it only leaked when there was a rush of water (like if the sink was full and I released the drain stopper).
After we applied the TFE paste, it leaks whenever we turn on the water. Just a drop every 5 minutes or so.
I am out of ideas. What advice can you offer?

Joint that is leaking under kitchen sink built into island

Best Answer

Neither tape nor putty should be used with a plastic compression joint. Tailpieces like that sometimes have flat washers when you probably need a tapered one--it should be the same as those at the other joints.

Have you gone beyond hand-tight with the nut? Sometimes an extra half-turn with a large pliers seals the deal. Just support the pipes when you do it.