Fixing a Slow-Draining Bathroom Sink

Drainage issues in a bathroom sink are rarely a sign of a major plumbing failure; they are usually just the inevitable result of life in a busy house. Over time, hair, soap scum, and toothpaste residue form a stubborn sludge inside the pipe that acts like a dam, gradually choking off your flow until the basin takes forever to empty. Getting it back to normal is a satisfying DIY win that requires nothing more than a few basic tools and a bit of patience. When done well, the water will spiral down the drain with a clean, audible roar, and you will have saved yourself a service call from a professional plumber who would charge triple to do exactly what you are about to accomplish.

  1. Remove the Stopper First. Unscrew the nut holding the horizontal pivot rod to the back of the drain tailpiece beneath the sink. Pull the rod out far enough to release the stopper, then lift the stopper out of the drain to clean off accumulated hair and debris.
  2. Catch the Spillage. Place a bucket directly underneath the P-trap, which is the U-shaped pipe section beneath the sink. This bucket will catch the standing water and debris that spills out once the connections are loosened.
  3. Loosen and Lower the Trap. Unscrew the two slip nuts on either end of the P-trap using your hands or channel-lock pliers. Carefully lower the pipe section into the bucket to drain the trapped water.
  4. Scrub Away the Buildup. Take the P-trap to a utility sink or outside and flush it out with a hose or high-pressure spray. Use a bottle brush to scrub the inner walls to remove stubborn, hardened buildup.
  5. Inspect Deeper Obstructions. Look into the wall-side pipe with a flashlight to ensure there is no blockage further down the line. If you see debris, gently feed a drain snake or a stiff wire into the opening to dislodge it.
  6. Verify the Flow Works. Slide the P-trap back into place, hand-tightening the slip nuts to ensure they are snug but not overtightened. Run the hot water for two minutes to check for leaks at the joints and verify the flow rate.