How to Unclog a Slow Bathroom Sink Drain

Step-by-Step

1. 1

   Step 1: Check How Badly It Is Draining

   Run the tap and watch. A slow drain is usually a partial clog near the stopper. A sink that will not drain at all, or that backs up when other fixtures run, points to a deeper problem that may need a plumber.

   Pro tip

   Note whether other drains in the house are also slow — that changes the diagnosis.
2. 2

   Step 2: Clear the Area Under the Sink

   Empty the cabinet, lay down old towels, and put a bucket within reach. You want a clear view of the drain assembly and the pivot rod behind it.

   Pro tip

   Photograph the assembly before touching anything.
3. 3

   Step 3: Remove the Sink Stopper

   Some stoppers lift straight out. Others are held by a pivot rod behind the drain that must be unscrewed or unclipped first. Loosen the nut by hand or with pliers, slide the rod free, then lift the stopper out from above.

   Pro tip

   If you loosen the pivot rod, keep track of the clip and nut — they are easy to lose in the cabinet.
4. 4

   Step 4: Pull Out the Hair and Buildup

   Wearing gloves, remove the hair and soap residue wrapped around the stopper and just inside the drain opening. This alone fixes most slow bathroom sinks.

   Pro tip

   An old toothbrush cleans the stopper and the inside lip of the drain quickly.
5. 5

   Step 5: Reinstall and Test With Hot Tap Water

   Put the stopper and pivot rod back, tighten the nut snugly, and run hot tap water for a minute. If the sink now drains normally, you are finished.

   Pro tip

   Confirm the stopper still opens and closes properly before moving on.
6. 6

   Step 6: Open the P-Trap If It Is Still Slow

   Place the bucket directly under the curved trap beneath the sink. Loosen the two slip nuts by hand, or gently with pliers, and lower the trap. Expect standing water to pour out.

   Pro tip

   Take a photo first so washers go back in the same orientation.

   Watch out

   Do not open the trap if a chemical drain cleaner has been poured into the sink — the trapped liquid can be caustic.
7. 7

   Step 7: Clean the Trap and Reassemble

   Clear debris from inside the trap with a bottle brush and rinse it out. Reinstall it with the washers seated correctly and tighten the slip nuts snugly by hand, adding only a small turn with pliers if needed.

   Pro tip

   Plastic slip nuts crack easily — snug is enough.
8. 8

   Step 8: Run Water and Check Every Joint for Leaks

   Run water for a full minute, then dry the joints with a paper towel and feel around each one. Check again after a few hours before putting cabinet contents back.

   Pro tip

   A dry paper towel finds slow drips your eyes will miss.

Tips

• Look under the sink first: many stoppers are held by a pivot rod behind the drain that must be loosened before the stopper lifts out.
• Work over a bucket and old towels so trap water does not reach the cabinet floor.
• Take a photo before disassembling the trap so the washers go back in the same orientation.
• Run water for a minute after reassembly and feel every joint for drips.

Common Mistakes

• Pouring in chemical drain cleaner before checking whether the clog is visible hair at the stopper.
• Mixing drain products, which can create dangerous reactions.
• Overtightening plastic slip nuts, which cracks them.
• Losing or reversing the trap washers during reassembly, causing a slow leak.

Frequently Asked Questions

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