Weekend P-Trap Blues

I’m at my wit’s end. I’ve taken apart and reassembled P-traps probably dozens of times over the years. None have really given me any trouble. Yesterday I met my match.

My master bath sink was draining very slowly. I took the P-trap apart, and cleaned out all the components (OMG the sludge that had built). Great. I assemble it all back. I put a bucket underneath just in case, turn on the water, and water starts dripping out at the first compression fitting. Tightening didn’t help. No problem, I think. I must have seated it incorrectly or it must not be straight, or whatever...I take it apart, reassemble. Same thing. Hm. OK. Probably the washer needs replacement. Go out to my garage, find a 1-½ to 1-¼ reduction washer. Reinstall the P-trap. Still leaks. OK. I go to Lowe’s, get a replacement P trap just in case there’s something wrong with either the P-trap or the spare washer I had. Still leaks.

I’ve now assembled and reassembled the P trap probably 20 times, hoping at some point, it’s finally going to take. But no. I’ve tightened lightly, and I’ve tightened the crap out of it, and I’ve tried everything in between. There are no dents or kinks in the sink pipe. The washer fits snugly on the pipe. Yet, water is somehow flowing up and out through the fitting.

I am out of ideas. What could possibly be going on here? And more importantly, how can I fix it and regain my sanity?

I think your pipe is still plugged down stream or the trap.

bud16415 said:

I think your pipe is still plugged down stream or the trap.

Click to expand...

Hm. Definitely not the trap. From the sink to the stub out, it's clear as day. Now...after that, you might be right. I can't see past the turn. And I don't have a scope...but I went ahead and ordered one on Amazon, so I'll soon find out.

But here's my question on that. Wouldn't a compression fitting be water tight at least for draining purposes (near zero pressure)? I mean, I would hope I could completely plug and fill the drain line without any leaks. Not so?

OK. I think I eliminated that possibility with a little logic. If the drain was plugged downstream, then running the faucet at full blast would fill the entire drain up and into the sink fairly quickly. After all, only a little bit of water is escaping through the fitting. And if only a little were getting through the theoretical clog down the line, that's a lot of water not going anywhere but up. And I can see that the water level barely gets up above the fitting. So, no...I don't think that's what's going on. Again, I'll be able to confirm 100% when I get my scope, but it just doesn't add up. That said, thanks for the idea.

I've used a number of things to correct the same event in the past, PASCO faucet lube and teflon tape have ilicited the best results, so far.

And you are absolutely sure the leak is at the joint of the trap and the tailpiece? In taking the trap loose you didn't disturb something above and you have a slight leak above that is collecting on the joint and appears to be leaking there? I fight leaks at the sink bottom more than anything else. Just a thought.

Oh god...I'm such an idiot. Fireguy, I owe you a virtual beer. This is almost too embarrassing to admit, but I'm not going to leave readers hanging...

I forgot to re-install the stopper actuator arm, and so the water was indeed coming from above (not flowing up through the fitting. Of course, the actuator arm enters through the back, so it wasn't visible to me, and...out of sight, out of mind.

All jokes now welcome. Thanks folks. Love how DIYers as a community help each other out.

One good thing to come out of this...I'm now getting a scope I've wanted for a while. Win on that end.

I don't want to talk about how many times I have had to mop up the bottom of the vanity again because I forgot to put the stopper lifter and nut back in place before I ran water.

I once turned the water back on after putting line stops under a sink not realizing all four were open. Talk about water everywhere.

Falls under stuff happens. Or as I used to tell my firefighting students, "Murphy is always in play!" I.E. Murphy's Law

It happens to the best of us.

All is well that ends well, or to paraphrase my high school teacher “ Houserepairtalk is not big enough to have a village idiot so we all take turns.”


Getting back to your drain the water should never stand that high in the trap, it should take all you can give it and stay well below that opening or the seal you were thinking it was. My guess is you still have a restriction down stream and your new scope may show it or just run a snake around the corner. If the trap was as gunked up as you said the rest is likely slowed down also.

OP - Is that a steel pipe leaving the sink? If so, does it have a flange at the bottom where the cone washer goes? I'm think that the leak occurs because the cone washer doesn't have anything to snug up against. Other than that, >