RepairUpdated June 22, 2026
Seeing water collecting under your kitchen sink is never a good sign. When it's coming from the bottom or side of your garbage disposal, that leak can lead to cabinet damage, unpleasant smells, and even mold. In Markham, we see this problem more often in homes built during the mid-20th century, which make up much of the area. Many of these homes have older sinks, drains, and disposals that have been through decades of daily use.
Why Garbage Disposals Leak Underneath
There are a few spots a disposal can leak, but when water drips from underneath, it usually signals a problem with the unit itself. Common causes include worn-out internal seals, corrosion inside the chamber, or cracks in the housing. Markham's moderately hard Lake Michigan water can speed up corrosion if a disposal is already several years old. Hard water allows mineral build-up inside the chamber, which puts extra wear on seals and metal parts.
Warning Signs Your Disposal Leak Needs Attention
- Water pooling under the sink, especially after running the disposal
- Mold or musty odors coming from the cabinet
- Damp or warped wood around the base of the cabinet
- Rust stains or mineral deposits visible on the outside of the disposal
- Strange noises when running the unit, like grinding or clattering
If ignored, leaks can keep damaging cabinetry or cause electrical issues if water drips onto wiring. Older homes in the south suburbs sometimes still have galvanized drainpipes or fittings that won't tolerate steady dripping. That's when leaks turn from a nuisance into a plumbing emergency.
What Our Crew Checks First
We start by drying the area and running the sink so we can watch where the water comes from. If the leak is coming directly from the bottom of the disposal, it's likely a failed internal seal or a crack. Side leaks where the disposal connects to the sink flange or the dishwasher inlet can often be fixed by tightening fittings or replacing gaskets.
If the disposal is leaking at its connection to the drainpipe, we check the slip nut, rubber gasket, and P-trap for wear or misalignment. Sometimes, an old P-trap (especially if it's cast iron or galvanized) will need to be replaced along with the disposal. You can find more info on how we handle pipe repairs and repiping for aging plumbing in Markham homes.
Repair or Replace?
If the leak is coming from the bottom housing or the reset button area, the internal seal is probably shot. Manufacturers don't design these parts to be resealed. In that case, we recommend replacing the disposal. For side or flange leaks, we'll try new gaskets and tightening all connections first.
Repeated leaks, electrical problems, or visible rust on the body are all signs the unit is at the end of its life. If you're upgrading your kitchen, our team can help with new faucet and fixture installation along with a disposal replacement for a complete update.
Preventing Future Disposal Leaks
Even a new disposal can develop leaks if the plumbing isn't properly installed. In older homes with clay-rich soils, like much of Markham, settling can shift plumbing connections under the sink. Our crew checks for any movement at the sink base and supports piping with brackets if needed. We also make sure to tighten mounting assemblies evenly and use the right plumber's putty or gasket, depending on your sink material.
For any kitchen drain clogs or slow drainage, a proper drain cleaning helps prevent back-ups that stress the disposal seals. If you see signs of water pooling elsewhere, our crew also handles leak detection and repair to spot hidden issues before they become major problems.
Know When to Call an Expert
Leaks inside the disposal unit itself usually mean it's time for a replacement, not a patch job. Attempting to repair cracks or failed seals is rarely successful for long. If you're dealing with repeated leaks at pipe joints or drain connections, this may signal a larger issue with old galvanized or corroded piping common in Markham homes. We're happy to talk through your options and inspect the full drain assembly as part of any garbage disposal service visit.
If you notice a wet cabinet base or hear drips from under your sink, our team can help. Call us at 708-729-6560 and we'll get a plumber out to assess your disposal leak and take care of it for good, so you can get back to a clean, dry kitchen.