Isolating the source of a leak under the sink.

[sycamore]

How do you begin to isolate the source of a leak? I have a moldy cabinet bottom with a pool of water undr my sink.

I took the PVC pipes off the sink drains and cleaned them out. There was a lot of gunk in one area, almost clogging the pipe entirely. There is still gunk in the pipe coming out of the wall, I have used a pen to remove some of the debris, and a snake- but there is still some debris in there. The smell drove me from the room it was so bad.
The cabinet doors are open to air out, and all the items have been removed from the cabinet.
What next?

[HayZee518]

look with a flashlight to see where the water is coming from. may take a while if there is a drip once every few minutes. next check the feeds to the fixture. tighten the 3/8 gland nuts about a quarter turn clockwise. next on the drains. replace all the slip fitting washers. tighten hand tight add a quarter turn with a channel lock plier.