About a year and half ago, we remodeled our second story master bathroom which involved moving one sink across the room (about 12'). The new vanity sits approximately where the bathtub previously was. I don't recall how the plumber ran the drain line from this sink - across to the old tie-in or somehow used the bath tub drain (I suspect the former and I wish now I had taken pics).

This is my wife's sink. She has been complaining of slow draining for months. She also said that this drain never really worked right. So, I finally looked into it. I pulled off the trap, pulled the pop-up drain and cleared the path all the way to the wall (very messy). I figured that had to be it. WRONG!!! It still drains slowly.

The arm of the trap goes into a 45deg fitting (drain pipe connect comes out of the wall at an angle). I thought the trap tube might be going into this fitting too far. So, I cut it down. I cut it multiple times until it was too short and ultimately replaced it (had a spare in the garage).

Here's the odd part. . . if I fill the sink up and DUMP the sink (like you do to test the connections underneath), the water drains pretty fast and even generates the tornado swirl thingee at the drain. But, if I just run the water, it starts backing up. If I let it get to about 1/2 the level I used in the dump test above, it takes at least 5 times as long to empty the sink.

One other thing . . . the drain pipe in the wall seems to have a little residual water in it lying on the bottom of the pipe - like there might not be enough fall in the line, blockage or something. I did run a snake through the line for about 6' and found nothing.

The plumber that did the work on this wasn't the brightest bulb on the tree (as we found out too late). So, I wouldn't put anything past what he might have done. And, it is quite possible that this problem existed from the start and I just didn't pay enough attention to my wife's complaints (although I'll never admit to saying that!).

Sorry for the long winded description. But, I don't know how else to communicate what I have going on.

I would suggest calling a plumber to snake the drain before anything else. It's entirely possible that the plumber tied into the old tub line and it was almost clogged when the work was done. You may have been putting up with this the whole time.

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Wow!!! Talk about a quick response. Thanks.

I will follow your suggestion and get it snaked out. But, I'm still curious why the DUMP method of draining the sink goes fast while the trickle method (where the plug is open and the sink just backs up) takes forever to drain by comparison? Is the sudden weight/pressure of the DUMP pushing the water through the clog where the trickle allows the clog to close up?

Could be because there is so much air in the water as it bubbles from the aerator that it is more difficult for the water to drain.

Best Wishes

what happens if you remove the stopper and then try the 'trickle' method?
is it draining now? if yes, it's air lock under stopper. No quick fix here, if stopper is adjusted to reach max height when rod is pushed down.

I didn't try the trickle method with the stopper out. I suppose I can try that. I think there may still be some adjustment left on the stopper.

Is this a vessel sink, or some other model without a pop up? Your description of the drainage is commensuate with one. When the water is flowing from the faucet directly onto the drain plug it is injecting water into the drain where it gets trapped and prevents drainage. Have you tried draining it without the pop up plug in place? If it then drains good, then you have an air bubble problem.

If, by vessel sink, you mean one that sits on top of the counter, then "no" it is not a vessel sink. This is an undermount sink that is an integrated furniture style vanity with a granite top and the white ceramic sink (purchased at Costco). It does have an overflow hole.

I do have the pop up drain (California Faucets). I will try removing it. However, I did try the following. I placed a 2 gal bucket under the drain tube with the trap off just to see if water was free flowing to the trap (i.e. not restricted at the plug). It flowed perfectly. However, I am assuming that having the trap on and connected to the drain line would cause back pressure that might help create this bubble effect.

Could this be a venting issue? If my plumber connected this to the tub drain line (which I suspect he did) and its vent is above the tub drain but below the basin drain, would it cause this kind of issue?

I would first have the line snaked to see if it is clogged.

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If it is a bubble effect it is strictly a sink drain fitting issue, possibly because the popup is not rising far enough, but it could also be an installation error.

Shouldn't be the problem or the cure, because they get excellent drainage when water is dumped into the sink. A double trap could cause the symptoms but we do not get any indication that this is the problem.

By "double trap", are you suggesting that the plumber left in the old tub trap and connected the sink drain to a line that flows through it (sink trap + tub trap)? FWIW, the tub was moved. So, my statement that he probably tied it into the tub drain line meant the OLD tub drain line.

He may have done that, but if so he also had to cut some other corners also. Without seeing how he did it, everything we say is just guessing.

I think you guys hit it on the nose with the pop-up drain bubble. I tried running the water while holding up the plug as far as I could and it makes a huge difference. As soon as I get a chance to get under there, I'm going to adjust the pop-up to come up more when open. I have a feeling that's going to do it.

Thanks for the help. This forum is awesome!!!!!!!!!