Quick Answer:
If your sink stopper stays open and the basin won’t hold water, start by inspecting the stopper and the drain seat. In most cases the stopper is misaligned, upside down, or not seated properly. Remove the stopper, clean any debris, check its orientation, and re-seat it. If linkage or rod parts are visibly damaged, you may need replacement or a professional.
Why This Happens
- Stopper not seated on the drain seat — it can be off-center or upside down.
- Debris, hair, or mineral deposits under the stopper prevent a seal.
- Lift rod, pivot rod, or linkage is bent, disconnected, or broken.
- Corrosion or worn rubber parts no longer form a seal.
- Incorrect installation or wrong stopper type for the drain.
Step-by-Step What to Do
Step 1 — Prepare and protect the area
- Place a small bucket or towel under the P-trap to catch water or small parts.
- Have gloves and a flashlight handy. Clear the cabinet under the sink for room to work.
Step 2 — Try a simple lift and inspect
- Operate the lift rod gently to see if the stopper moves at all. If it won’t move, don’t force it.
- Look into the drain to see if the stopper is centered on the seat. Check whether the stopper is upside down or not centered on the drain seat — a stopper placed incorrectly won’t seal.
Step 3 — Remove the stopper (common methods)
- For lift-and-turn stoppers: unscrew or pull out the knob on top, then pull the stopper up.
- For pop-up stoppers: reach under the sink, find the pivot rod that connects to the stopper, and remove the retaining nut to free the stopper.
- If you’re unsure which type you have, move the lift rod and watch the linkage under the sink to identify the connection point.
Step 4 — Inspect and clean the stopper and seat
- Check the stopper for hair, gunk, or mineral scale. Clean with warm soapy water and an old toothbrush.
- Examine the drain seat and the rubber sealing surfaces. Clean away build-up so the stopper can sit flush.
- Confirm the stopper orientation and that any rubber gasket is positioned correctly before reassembly.
Step 5 — Reassemble and test
- Reinstall the stopper the same way you removed it, making sure it sits centered on the seat.
- Operate the lift rod gently to check sealing. Fill the sink with water to confirm it holds.
- If the stopper still won’t seat, check the pivot rod and linkage for play or damage. If linkage looks snapped, see Stopper rod broken.
Step 6 — Other checks
- If the assembly appears intact but the pop-up behaves differently, see Pop-up drain won’t open for related troubleshooting.
- Consider replacing worn rubber seals or the stopper if cleaning doesn’t help.
What Not to Do
- Do not keep yanking the lift rod if it feels stuck—inspect the drain seat first.
- Do not use excessive force with pliers or screwdrivers; you can bend linkage or break parts.
- Do not pour harsh chemical drain cleaners into the sink to try to loosen the stopper; these can damage seals and finish and are unsafe to work around.
When to Call a Professional
- You can’t remove the stopper or parts are corroded and seized.
- The pivot rod or internal linkage is broken, stripped, or too difficult to access safely.
- Repeated leaks occur after reassembly, or the drain seat itself appears damaged or corroded.
- You prefer not to work under the sink or the sink is a delicate material (stone, glass) that requires professional care.
Safety Notes
- Wear gloves and eye protection when working under the sink.
- Place a bucket or towel under the P-trap to catch water and small parts.
- Avoid chemical cleaners while disassembling parts. If chemicals were used, ventilate the area and rinse thoroughly before working.
- Work gently to avoid scratching sink finishes or breaking plastic components.
Common Homeowner Questions
- How do I know if the stopper is upside down? — Remove it and look for the sealing surface and any rubber washer; if the flat sealing surface isn’t facing down, flip it.
- Can I replace just the rubber seal? — Yes, many stoppers have replaceable seals available at hardware stores and they’re an inexpensive first fix.
- What if the pivot rod won’t come loose? — Apply penetrating lubricant sparingly and wait, or call a plumber to avoid breaking the rod or nut.