How to Clear a Slow Bathroom Sink Drain

Drainage issues in the bathroom usually signal that hair, skin cells, and soap scum have formed a clog right at the mouth of the plumbing. Most people reach for chemical drain cleaners at the first sign of slow water, but these caustic liquids often damage older pipes and fail to reach the solid mass of debris actually causing the backup. A successful repair requires a hands-on approach that clears the obstruction physically rather than chemically. When you tackle the trap directly, you ensure the blockage is gone for good and avoid the long-term risk of pipe corrosion. A clean, free-flowing drain is simply a matter of clearing the path and checking the hardware.

Fish Out the Stopper. Unscrew or lift the pop-up stopper out of the drain opening. Use a pair of needle-nose pliers or your fingers to pull out any clumps of hair and debris stuck to the mechanism.
Catch What Spills. Place a bucket or a deep plastic bowl directly under the P-trap, which is the curved pipe beneath your sink. This will catch the stagnant water that is bound to spill out as soon as you loosen the fittings.
Crack the Nuts Loose. Use tongue-and-groove pliers to turn the plastic slip nuts on both ends of the U-shaped pipe. If the nuts are metal and frozen, apply a light coat of penetrating oil and let it sit for ten minutes before turning.
Scrub the Trap Clean. Pull the U-pipe free and dump the contents into your bucket. Use a small bottle brush or a stiff wire to scrape out the internal walls of the pipe, removing the thick layer of gunk that narrows the path.
Push Through the Wall Line. Insert a plastic drain snake or a flexible auger into the pipe leading into the wall. Twist the snake to catch any hair clumps deeper in the line and pull them out until you feel no further resistance.
Reassemble and Verify. Slide the P-trap back into place and hand-tighten the slip nuts firmly. Run hot water through the sink for two full minutes to flush the lines and check for any leaks at the joints.