Quick Answer:

Hair and soap build up near the stopper and in the trap can stop water from flowing. Start by checking the stopper area and the P-trap for hair clumps, then flush the overflow opening after your shaving routine to move any trapped debris down the drain.

Why This Happens

Shaving produces lots of short hairs and small soap particles that stick together. The stopper area and the P‑trap are common places for that material to collect. When the main drain slows, water finds the overflow opening and can back up there instead of flowing away. That overflow can also hide trapped hair and soap film that keeps refilling the sink as you use it. If the problem seems tied to the sink filling, remember that Overflow only leaks when sink full, which usually points to a drain/stopper blockage, not a separate overflow leak.

Step-by-Step What to Do

1. Clear the stopper area

• Put on disposable gloves. Remove or lift the stopper (many pop-up stoppers pull straight out or unscrew from under the sink).
• Use a paper towel, tweezers, or a small brush to remove visible hair and soap clumps from the stopper and the drain entrance.
• Replace the stopper and test the flow by running water.

2. Check and clean the trap

• Place a bucket under the P‑trap to catch water. Loosen the slip nuts by hand or with adjustable pliers—do not force them if they seem stuck.
• Remove the trap and dump its contents into the bucket. Wipe away hair and sludge, then rinse the trap with water.
• Reassemble the trap, hand‑tighten the nuts, and check for leaks by running water through the sink.

3. Flush the overflow opening after shaving

• After you shave, use a cup, sink sprayer, or a small hand pump to force a few strong flushes of water down the overflow opening. This helps push hair and soap film through the overflow channel and into the drain.
• Do this routinely after shaving sessions to prevent build-up.

4. Test and repeat if needed

• Run a steady flow of warm water for a minute and watch for backup at the overflow. If flow improves, you’re likely clear. If not, repeat cleaning the stopper and trap or try a small drain snake for the immediate drain.

What Not to Do

• Do not keep shaving into the sink until you confirm hair isn’t building up at the stopper/trap.
• Do not poke deep into the overflow channel with metal wires or sharp tools—you can damage the finish or internal parts.
• Avoid pouring strong chemical drain cleaners into the overflow; they are less effective there and can be hazardous.

When to Call a Professional

Call a plumber if:

• The sink continues to back up after cleaning the stopper and trap.
• You smell sewer gas or see persistent standing water under the sink.
• You notice staining, damp drywall, or mold near the sink—signs of Overflow leaking inside wall or a hidden leak that needs inspection.

Safety Notes

• Wear gloves and eye protection when handling trapped debris or working under the sink.
• Put a bucket under the trap before you loosen fittings to avoid spills.
• If you use any drain product, read labels and follow safety instructions. Prefer mechanical cleaning (removing hair) to chemicals.

Common Homeowner Questions

• Why does hair always collect at the stopper?
  Short answer: The stopper narrows flow and traps hair as water slows down there.
• Will a drain snake fix this?
  Short answer: A short hair snake can help the immediate drain but won’t reach the overflow channel—clean the trap and flush the overflow too.
• How often should I flush the overflow after shaving?
  Short answer: A quick flush after each shave or at least daily if you shave in the sink regularly will prevent buildup.