one final question related to the sink leaking!

[JJ]

One final question here and that has to do with the sink leaking. While I was trying to use the plunger in the bathroom sink in an attempt to restore drainage, I suddenly noticed water on the floor. It seems to be coming from around the top of the sink, perhaps around drain itself. While I could probably repair this, as I have done with the kitchen sink in the past, I am more concerned that it might be the porcelain. There is one area right around the drain pipe/ porcelain area that has decayed a lot over the years and my plunging might have caused a small leak to form. Is there any way to fix the porcelain? If I had to get a sink, I'd never be able to match the colors with the rest of the bathroom and it would be costly. Thanks in advance.

[Retirednoguilt]

I've never plunged a sink without splashing water on the floor. I'd first watch carefully for future leaks just from filling the sink 1/2 full of water and letting it drain out. In other words, with normal use. If no more leaks, I wouldn't push the panic button. Decay around the porcelain sounds like there's rust formation underneath the porcelain. Just as with auto body rust, don't just try to patch the area with some waterproof material unless you plan to move in the near future. The underlying rust will slowly but surely spread and eventually allow a wider area of overlaying porcelain to fail. No hard and fast rule that the sink must match other colors in the bathroom. Consider a stainless steel sink, which won't clash with any color.

[JJ]

Ok, the good news is that the leaking doesn't appear to be emanating from the porcelain. I filled the sink, then quickly stopped it. No water dripping. When I removed the stop, I got dripping as the water drained away. So, it looks like it's in the piping somewhere. I wouldn't say at the top otherwise there'd be leaking when stopped I would think, so somewhere near the top.

[Retirednoguilt]

If you have a typical sink stopper mechanism, there's a vertical rod near where the faucet comes up from the sink. That rod controls the plunger going up and down as that vertical rod is moved up and down. Under the sink, there's a diagonal, nearly horizontal rod that transfers the up/down motion of that rod to the waste line and is called a "pivot rod". Where the pivot rod connects to the waste line is a pivot nut which has an associated gasket between the nut and threading on the side of the drain pipe. When the pivot nut is very tight, it will prevent the rod from moving up and down. If too loose, or if the gasket is corroded, torn, worn etc., there will be a leak when the drain pipe is draining water from the sink. Take a towel or paper towel and make sure the area right around the pivot nut is dry. Run some water. See if that area now is wet. If so, you found your leak. First try tightening the nut a little. If that doesn't stop the leak, perhaps the gasket needs to be replaced. Another popular leak source is a corroded spot at the very bottom of a metal sink trap or rarely a crack in a PVC sink trap. Check the bottom of the trap making sure you have good lighting. Again, make sure that area is really dry, run some water in the sink and see if that area becomes wet. If it's wet and you see a crack or corroded area, replace the trap.

[Scott Lurndal]

Modern big-box hardware metal store traps are notoriously thin[*], if your water (e.g. well water) isn't close to a neutral PH, the thin walls of the trap can deteriorate and the snake can make holes in the trap or wall outlet extension.

[*] pay for the heavy gauge plated brass rather than the thin SS traps, or go plastic.

[rbowman]

O-ring in the trap?

[trader_4]

+1

Basically get under there with a flashlight and paper towels and figure out what's leaking. Before the second post, I thought it might be deteriorated plumbers putty at the drain, but since it doesn't leak when plugged, can rule that out.