How to Unclog the Sink
The first thing to do if you sink is clogged is to make sure it is the only drain with this problem, and
that others on other floors don't share this plugging (could be a stop in the drain stack or main).
If you favor chemical cleaners these might work on less than complete blockages - anything greater
will probably take more physical measures.
1) If there is a double-sink bowl, with a garage disposal, remove the water from the
disposal side. Stuff in a rag to stop its drain.
2) Take out and set aside the strainer. Remove any debris or blockages seen above the grate.
3) Wearing goggles or protective eyewear, place a plunger in the water-backed sink.
The short handle plungers form a decent seal, although traditional cup plungers
should do the job.
In any case, make a mental note of not mixing toilet and sink plungers which is unsanitary.
4) Push down on the plunger handle to let out the air - with the bottom at a slight angle to do this.
Then, holding on tight, with the stopped-water-level forming a seal, pump it, acting on the force of inward
and outward air pressure. If you seem to not be getting an adequate seal, finger on some petroleum jelly around
the rim of the plunger.
Pump on the drain vigorously, repeatedly. Relieve the plunger quick.
5) If the water starts to exit, flush it with very hot water. If the water does not move then remove the trap;
a) As an added measure, turn off the water supply. If there is more than one level to the home
you may wish to flush all toilets.
b) Place a small plastic bucket under the trap with an old clean up towel nearby.
c) Remove the slip nuts at both ends of the drain trap by hand or by using a pair
of channel lock pliers. The plastic washers should really be replaced. Many plumbers do re-use them.
d) Clear out the plug with a flexible brush or rag. Wipe clean the inner surface with a mild detergent.
Re-assemble unless there has been no blockage.
If nothing had been blocking the pipe, the tougher clog
will need to be snaked with an auger into the branch drain.