So I have this thing https://www.homedepot.ca/product/moen-all-metal-pop-up-drain-with-overflow-brushed-nickel/1000837835

and it is freaking leaking, driving me crazy. I tried caulk and it leaked. Then I tried putty and it is still leaking and I can't figure out why and where. If I am leaving water in the sink for a while I am seeing/feeling humidity in the area marked with the red arrows. enter image description here

As far as I understand the construction of this thing the water could leak via two ways (red path or the blue path in the above picture) How do I determine which way the water is leaking? Is it possible to fix this by using Teflon tape or thread dope ? Should I even try that since the water is leaking from somewhere above in the first place ? Assuming everything is solid with the pop up and with the putty I am assuming the water could sit there in the overflow cuts from the last use of the drain and then it leaks down through the white and red gaskets. I suspect that this is what is giving me grief since the water in the sink does not seem to go anywhere ...this is not a masive leaking it would take maybe more than an hour or two to see a drop in the pan that is sitting under the drain right now. The reviews on the home depot side are not that great and the 1 star reviews complain about the same issue-leaking

enter image description here

  • 3
    The leak is caused either by defective materials (the pop up assembly or the sink) or from improper installation. There is no way anyone here can know the cause. A guess would be the bottom nut has not been tightened enough or improper application of the plumbers putty. This is necessary to seal the drain flange to the sink bowl. Never use caulking in place of the plumbers putty and the thought to use teflon tape or pipe dope on the threaded pieces is absolutely wrong.
    – Kyle
    Sep 4, 2022 at 16:37

3 Answers 3


Make sure the clear washer underneath is aligned correctly, then tighten more than you already have.

Be sure to have engaged all the threads when attaching the basket (upper) to the tube, or it’ll tear apart when you put some real muscle to the nut.

A couple of drops means that you’re close to the right amount of tightness.

  • 1
    It is one piece ..the upper piece the basket is not attached via a thread.Are there any chances to crack the sink if I tighten that tio much?
    – MiniMe
    Sep 4, 2022 at 16:02
  • 2
    I tightened the nut like three of four more quarter turns and the leak stopped. Still watching it but that seems to have been the issue, selecting this as the answer as it was first posted, up votted everybody else as you were all right
    – MiniMe
    Sep 4, 2022 at 16:59
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    Glad you got it sorted. FWIW, you're way more likely to strip the threads on the popup than break the porcelain of a sink. My general rule is to see if it leaks, then tighten a bit more if needed. Sep 4, 2022 at 19:19
  • its not porcelain, it is polymarble so it is way more prone to cracking and a softer material isn't it?
    – MiniMe
    Sep 4, 2022 at 19:25
  • I don't have any experience with polymarble... maybe there's a question there. Sep 4, 2022 at 19:29

Sink bowls have a an internal passageway to provide a route for water entering the overflow drain opening; the opening is usually located at the user's side of the sink, just underneath the bowl's top lip. Water passing into the overflow opening runs into the space between the inner bowl (that holds the water when the sink is used) and the outer bowl, and then (via a slot in the body/flange) into the drain. (Note that the blue arrow in the illustration shows the slot, but shows water running in the opposite direction from correct operation.)

The "body" of the assembly (usually called the "flange") must seal to both the inner bowl and the outer bowl, so that water in the sink can only exit into the drain line by going down through the middle of the flange (because the drain pop-up is open). If one or both of the seals (flange-to-bowl on top, and bowl-to-drain pipe below) is defective, water will appear on the outside of the assembly.

Thus, the body/flange in your sink is not effectively sealed. This may be because a washer around the drain pipe is defective or insufficiently clamped, or may be because the top-end packing between the flange and the inner bowl is defective. In the US, this packing is a thick, compressible material called "plumber's putty."


You need to put putty between the plastic washer and the rubber washer under the sink.

The best way to do this is do your normal install with the putty on the top flange. Tighten the bottom nut snug almost finish tight so the putty comes out the top side of sink. You do this so you get the rubber seal pushed up against the sink as it would be when it's tight. Then loosen the bottom nut while supporting the drain so it doesn't move. Put a ring of putty around the drain between the plastic washer and the rubber washer. Retighten to finish tight. Remove any putty that seeps out and you are done.

I used this method for 25 years as a plumber and never had any leaks.

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