Odd bath sink drain leak

[davelinde]

Two weeks ago DW noticed that a towel stored under the bath sink was wet. She took everything out of the cabinet (no damage to the wood we were happy to see) then put a bowl in the middle under the trap. The bowl collected some water over a day or so... at which point DW informed me.

I find three drain connections there - one at the sink itself, then two on the trap. The sink seemed plenty tight so I undid the trap, squared it all up (the drain pipes were a little off) and re-tightened it. We left the bowl down there "just in case".

Well, the bowl stayed dry for two weeks or so, but yesterday I noticed that it had collected a bit of water again. I dumped the water, looked for signs of leaking and put the bowl back. So far... it's still dry. So this leak seems to come and go in an odd way.

Any ideas? If I can't find the leak it's hard to fix. For now the bowl is preventing water damage... but longer term I need to find and fix this.

 

[Ray LeTourneau]

I know there have been problems with the kitchen drains having the gasket installed inside the sink instead of on the bottom of the drain hole. You might check that for the bath sink. The other unusual possibility might be Hot water going down a cool drain pipe and cool cabinet causing a little condensation? Just a guess outside the box...

 

[jbeletti]

Dave,

In my unit, I had occasional water under my bathroom sink on the middle shelf. I could not determine where it was leaking from - specifically.

I put my camera on Macro mode with Flash on and put the camera under the sink and snapped a bunch of pics.

I downloaded the pics to my computer and reviewed them and sure enough, I found a pearl of water at cold water connections at the end of the Pex at underside of the faucet. I hand-tightened it a bit more - did the other side for good measure and all has been dry since.

Jim

 

[SmokeyBare]

Wrap several layers of tissue paper below each joint on the drain pipes... yes, tape it in place if you need too so it holds. This too might help tell you which joint is leaking...

Remember the rod that controls the sink stopper. it could also be a source for a leak.

Good Luck !

 

[Bob&Patty]

Marv, I never would have thought about the sink stopper rod. You fire guys have all the answers. Bob

 

[davelinde]

Wrap several layers of tissue paper below each joint

Now that's just too simple - why didn't I think of that in the first place. THANKS.

btw - I put a quarter turn on the hot and cold cnx with my fingers per Jim. Let's see what some tissue tells me.

 

[davelinde]

Got it!

I didn't get around to the tissues yet but today I figured this out. I just got out of the shower and noticed the shower drain was running slow - usually a sign the tank is getting full. Just then I noticed the bath sink drain gurgling and checked underneath. Sure enough the bowl (under the sink) was filling with water as it dripped from the higher joint in the J-trap.

Apparently when gray tank 1 gets too full the venting stops working on the bath sink, causing more water to sit in the trap. The higher water level exposes the leak. Next step it to take apart the trap and figure out why it's not water tight.