A slow or clogged bathroom sink is almost always caused by accumulated hair in the drain. There are two ways to fix that clogged drain. The first way is easy, using few tools. The other way is hard. Are you lucky today? Let's find out.
Remove the pop-up plunger. (Some styles may require that you withdraw the horizontal pop-up bar in order to lift out the plunger.) Check the flat blades on the plunger. If there is a large accumulation of hair and debris on the blades, clean them off.
Before you replace the plunger, shine a light down the drain from the top of the drain pop-up flange. You can see if there is an accumulation of hair in the pop-up assembly that is further causing the clogged bathroom sink.
If there is, try to hook it out from the top, or drop the “J” bend of the p-trap. Push any debris out of the open tail piece. Now reassemble the parts and try the drain again. If it is now clear, that was easy.
All that is left to do is set the pop-up in the closed position and fill the bowl of the fixture with tap water to the overflow. That is so you can check the water-tightness of the pop-up and drain joints.
Let the water out of the fixture while watching the piping below. If all is dry, you're done. Yes, you were lucky... fixing your clogged bathroom sink was easy! Bask in the glory of a job well done!
If you're still reading, I guess that the cause of the slow drain wasn't at the plunger or wrapped around the horizontal pop-up bar after all. You weren't lucky... you'll have to get out the drain snake.
there is good news- the hair plug is usually just past the trap arm a
few inches into the drain at the sanitary tee. Before you begin the
section where I have you working in that little cabinet, (or where a
pedestal is in your way), there may be a short-cut available to you.
Sometimes you can snake a clogged bathroom sink, or bathtub from the roof IF the drain in question is vented directly to the roof without any offsets. This may be the case when the fixture is on the highest floor, and alone on its side of the room, away from the toilet, so that it's vent doesn't join the toilet vent at mid wall. If the stars are aligned on this one the job can be a breeze. Please notice! I am not qualified to instruct you on roof and ladder protocol so for the record I am not telling you to get on a ladder or a roof!
Now where was I? Remove both sections of the P-trap, the J-bend and the trap-arm. If the trap-arm is not removable and is soldered to its brass trap adapter, that is a trap adapter (sometimes called a "sweat bushing”, or a lead drain. CAUTION: there is no threaded joint on a soldered lead pipe trap-arm. Go to trap adapter or lead pipe drains on this web site to continue.
Once the trap arm is removed you can see if your drain cable is going down the drain or up the vent. Run the cable end into the tee and down the drain about twelve to eighteen inches. Turn it so the open end of the cable head, if there is one, hooks into the drain obstruction.
Withdraw the cable either continuing to turn as before, or by just pulling straight out. If you've now removed the obstruction, replace all the parts and test the drain as above. (If no obstruction was removed you are officially unlucky today.)
Run the cable in again, this time either all the way in or until you think it has intersected with the drain of a well draining fixture, preferably the toilet.
Reassemble and test as above. If the drain is now clear, you have prevailed... well done. If not, reassemble the drain, put the tools away and clean up.
Don't get mad... you can't win 'em all. Trying to do it yourself is a good thing, but this time you need some outside help. It's time to call your trusted plumber to fix that stubborn clogged bathroom sink.
As long as I'm recommending that you call a plumber, if you're in the Portland Oregon metro area, you could call me! I'm Brian @ Brians Plumbing- 503-656-6192.