On the following picture, you can clearly see leak marks (the rust like traces on the grey pipe just under the sink). These are leaks that were let to dry and were never cleaned up. Yikes… Also observe the piece of teflon tape at the transition between the ABS pipe (black) and the PVC flexible pipe (white) just above the P-Trap (teflow is not a way to prevent leaks – it is a way to lubricate threads).
I have been investigating how to properly fix these, respecting code. I am running these ideas by plumbers and I’ll will soon share them with you so stay tuned!