bathroom clog - sink refilling w/ water. AC is connected

I seem to have a clog in my 2nd floor master bathroom sink. I don't have any other plumbing issues in the house.

The sink has been gradually draining slower and slower and is now fully clogged.

I tried plunging and then snaking but no real luck. Left for dinner last night with no water in sink, came home and sink was full (thankfully did not overflow). I took my wet vac and sucked out water from sink and drain. Took apart PVC trap under sink and saw nothing.

Went to bed, just woke up and sink is full again. What the heck?

lav drain

There has to be something else going on.
Is something else draining into that same stack?

plumber1 said:

There has to be something else going on.
Is something else draining into that same stack?

Click to expand...

Crazy, huh?

I don't know of anything else which drains into the stack (above the bath is an attic which could only drain a/c runoff [I suppose ?], and there is nothing happening w/ that) , the other side of the wall is the 2nd story of a 2-floor great room. The second sink and shower are on the other side of the bathroom and seem to hit another stack. We are intentionally not using them at this time. My floorplans don't detail the plumbing layout.

This is so confusing, although I have almost no plumbing skills - just basic fix the toilet or unclog a drain type stuff. And now I can't even do that!!

how about getting the drain line scrubbed? i've encountered this baffling situation before and it turned out to be an incredible amount of scum within the length of the line and snaking does nothing as you just end up boring a small hole through the centre. Scrub it from the inside out and i bet it'll be fine, this problem doesn't necessary show up in the other drains for it to be a problem for this one - lav is a much smaller drainline...
good luck to you

Has it been raining? On a second story bathroom, there is little that would fill a sink up. The fact that it doesn't drain is another issue. There must be a blockage somewhere below that sink. Rain down the vent or water from the a/c condensor is the only source that comes to mind to fill it up; a blockage keeping it from draining. The toilet and shower in that room drain normally, though, huh? If so, it is likely something between the sink drain, and the toilet, shower drain. Maybe your snake was not long enough, or it went the wrong way in a wye. My unprofessional opinion.

plugged drain

The lav drain normally drains into the stack or vent pipe.
Should not be more than three to eight feet to the stack.
Get yourself a top snake at Lowes or Builders Square. It's a snake thats coiled up inside a tapered can with an offset handle. $15 to $20. Take the pop-up stopper out of the lav and start working the little snake through. Don't take the trap apart. Once you get it through the trap, run enough water to back up so that you can watch the water level. Snake should go easier now and water will dissappear. keep running water while you pull the snake back out and you won't make a mess.

Thanks for the advice everyone.

One of the a/c units in the attic is draining into the same stack that the sink drains into. That is what is causing the sink to slowly refill. So, at least that mystery is solved....

I have already tried plunging (pouring boiling water in sink to boot) and snaking the line but no relief.

One question on the snake - how do I get it to go to clog?? After the trap, the line goes left to reach the stack. Could the snake be going up?? I use the type that is attached to a power drill - should I just use the hand crank type? It seems to have trouble getting through a number of areas that are clearly not the clog, I guess various bends and turns, any advice on getting the snake further, easier?? I should probably remove trap and go directly in from there, eh?

How much would a house call from Vancouver cost?

plugged lav

Again, 90% of the time you can clean with a top snake in a can. And it makes no mess. Other times a small RIDIGID electric drain cleaner works great. Once in a great while, that too can be a chore.
I can't see your conditions.
Besides the trap, there should not be more than one or two bends in the drain. And it's probably not more than eight feet in total length.
I think it's easier to use a manual snake in a can than a snake on the end of a drill motor. You will feel where you are going much easier............

If the AC Condensate is filling the lav from above, it stands to season that the clog is below the tee from the stack to the lav. Possibly you can snake down from the top, where the AC is going in to reach it.

John

Once you get the drain cleared, possibly by a plumber, you should see about getting that condensate drain disconnected from the stack. In the wintertime or any other time when there is low humidity, the trap will dry out and the air handler will draw sewer gases into the unit and then blow them throughout the house.