Likely cause: hair and soap scum on the stopper

Why this happens

Family Handyman says a slow bathroom sink is almost always caused by hair and gummy soap scum caught on the stopper or pivot rod. Bob Vila explains why: the stopper sits at the mouth of the drain with a tail that reaches into the pipe, so it catches hair, soap and other debris. HomeTips adds that the buildup collects on the stopper body, the pivot hole and the drain throat. Family Handyman rates the fix a beginner job.

How to fix it

1. Has drain cleaner gone down this drain? Then stop here. Do not pull the stopper, reach into the drain or take anything apart. Lowe's says not to use drain tools or remove a trap after a chemical drain cleaner, because you could come into contact with chemicals still in the water. Call a plumber and say what you used.
2. Turn the faucet off, empty the cabinet under the sink and set a bucket or bowl under the drain pipe.
3. Try lifting the stopper straight out, or lift and twist. Bob Vila says many modern stoppers simply unscrew.
4. If it stays put, close both shutoff valves under the sink by hand so the faucet cannot be run while the drain is open. If a valve will not turn, do not force it. Leave it alone and keep the faucet off instead. Then find the pivot rod nut on the back of the drain pipe under the sink. Unscrew it, pull the pivot rod back and lift the stopper out. Family Handyman says to use pliers if the nut will not loosen by hand. Delta's support steps for its pop-up drains work the same way: remove the nut that holds the horizontal rod, then lift the stopper out.
5. Pull the hair and gunk off the stopper and the rod. Fish hair out of the drain with a bent wire or a plastic drain snake, lifting it out often to wipe it clean. Go gently: Family Handyman warns that cable-tie tools can get caught or break off inside the drain.
6. Scrub the stopper with an old toothbrush and a mild cleaner or vinegar.
7. Check the rubber seal on the stopper while it is out. Lowe's says a stopper with a cracked or brittle seal should be replaced. HomeTips says to replace the stopper assembly if the pivot rod is damaged or the linkage is badly corroded.
8. Drop the stopper back in, line up the pivot rod with the slot in the stopper, push the rod in and hand-tighten the nut.
9. If you closed the shutoff valves, open them again. Run hot water to rinse out leftover soap scum and test the drain. Check around the pivot rod nut for drips.

When to stop. If the pipes under the sink are old or corroded, or you are worried about damaging them, stop there. Lowe's says that is the time to contact a professional plumber.

If you need the part

You only need a new stopper if the seal on yours is cracked or brittle. Match your old stopper before you order.

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