Quick Answer:
Water pooling at the sink opening usually means the seal where the disposal meets the sink is leaking. Stop using the sink, turn off the disposal power, dry the area, and follow the checks below to find whether the top seal is weeping or a lower connection is the problem.
Why This Happens
- The rubber or plumber’s putty seal under the sink flange can wear, shift, or dry out with time.
- The mounting ring or screws may be loose or misaligned, letting water bypass the gasket.
- Previous plumbing work or a bump to the unit can disturb the flange or gasket.
- Sometimes the leak only appears under use, or only after repairs — check the appropriate guidance such as Disposal leaks only when running and Disposal leaks after plumbing repair.
Step-by-Step What to Do
1. Stop water and power
- Turn off the faucet and the disposal power at the breaker before working under the sink.
- Do not rely on the disposal switch at the wall alone — cut the breaker to be safe.
2. Dry the flange area and run a controlled test
- Wipe the sink opening, flange edge, and the immediate underside dry with a towel.
- Close the disposal drain (if you can) and run water into the sink without the disposal running to see if the top seal weeps. This helps show if the top seal or the underside is leaking.
3. Inspect visible parts
- Look under the sink at the mounting ring, gasket, and any plumber’s putty. Check for corrosion, cracks, or displaced putty.
- Feel for moisture to pinpoint the exact drip source (top of flange, around mounting screws, or from the tailpipe connection).
4. Test mounting tightness and seal placement
- If the leak looks like it comes from the mounting ring area and the gasket appears in place, you can try tightening the mounting screws gradually and evenly. Only turn each screw a small amount in sequence to bring the ring up evenly.
- If the gasket or putty looks out of position, loosen the ring, reseat the gasket or replace the plumber’s putty, and retighten evenly.
5. Replace worn pieces if needed
- If the rubber gasket is cracked or the putty is crumbly, replace them — these are common, inexpensive repairs.
- When replacing, follow manufacturer instructions for the correct gasket and proper seating of the flange.
6. Re-test and observe
- Restore power and run water, then run the disposal briefly while watching under the sink for leaks. Test with water in the sink without running the disposal first to confirm the top seal is sound.
- Check again after several uses — some leaks show only after pressure builds or the unit vibrates.
What Not to Do
- Do not keep tightening the flange without checking seal placement; overtightening can deform gaskets.
- Do not work on the unit without cutting power at the breaker.
- Avoid using excessive force or improvised tools that can crack the sink or damage the mounting hardware.
When to Call a Professional
- If you find a cracked flange or sink bowl that needs repair or replacement.
- If tightening and basic gasket replacement don’t stop the leak.
- If the leak is coming from a hard-to-access area, the disposal needs removal and you’re uncomfortable doing it, or electrical issues are present.
Safety Notes
- Always disconnect power at the breaker before working on or under the disposal.
- Wear gloves and eye protection when handling old putty, gaskets, or corroded parts.
- Do not put your hand into the disposal chamber unless the unit is completely disconnected from power and you can see clearly inside.
Common Homeowner Questions
- Can I fix this myself? Yes, often by drying the area, testing the top seal, and replacing a worn gasket or putty.
- How long will a new gasket last? A good rubber gasket typically lasts several years but depends on use and chemical exposure.
- Will tightening always stop the leak? No — tightening helps only when the seal is still correctly positioned; a damaged or shifted seal usually needs replacement.