How to Fix a Garbage Disposal Leaking from the Bottom

A garbage disposal is one of those kitchen appliances you don’t think much about — until it starts leaking. If you’ve noticed water pooling under your sink, chances are your garbage disposal is leaking from the bottom, and that’s a problem you don’t want to ignore. 

The good news? You can often diagnose and fix it yourself without calling a plumber. Let’s go over the common causes, how to find the source of the leak, and what you can do to fix it.

Common Causes of Garbage Disposal Leaking from the Bottom

Leaks are most often caused by overuse or corrosion, but there are a lot of components that are vulnerable to these effects. Here’s where to look first:

Worn-Out Internal Seals

Garbage disposals contain internal seals that keep water from leaking out. Over time, these seals can wear down due to constant exposure to water, food particles, and pressure. If your garbage disposal is leaking water from the bottom, chances are the internal seals have given out. This is especially common in older units that have been running for years.

Cracks or Corrosion in the Unit

If your rusted garbage disposal is leaking, you may be dealing with cracks in the internal components or the outer casing. Rust and corrosion happen naturally over time, especially if your disposal has been exposed to excessive moisture or hasn’t been maintained properly. Once cracks form, leaks are inevitable.

Loose or Damaged Discharge Pipe

Your garbage disposal is connected to your home’s plumbing via a discharge pipe. If that pipe becomes loose or damaged, it can lead to leaks. Sometimes, it’s just a matter of tightening the connection, but in other cases, the gasket, pipe, or garbage disposal may need replacing.

Faulty Sink Flange or Gasket

The sink flange is what connects the disposal to the sink, and it’s sealed with a rubber gasket and plumber’s putty. Over time, these seals can weaken, leading to leaks. If your garbage disposal is leaking but you’re not sure from where, this is one of the first places to check.

Overuse or Clogged Drain

If you’re constantly using your disposal to grind up heavy food scraps, it can put strain on the unit. A clogged or slow-draining disposal can cause water to back up, which might make it seem like it’s leaking when the real problem is a blockage further down the line.

How to Identify a Leak in Your Garbage Disposal

If you want to repair your garbage disposal, the first step is to figure out what’s wrong. As with fixing any appliance, it’s important to follow protocol to stay safe and on task.

Turn Off the Power

Safety first! Before touching your garbage disposal, make sure to turn off the power at the circuit breaker. This ensures you won’t accidentally turn it on while inspecting for leaks, which can be extremely dangerous.

Dry the Unit and Observe

Use a towel to dry the entire disposal. Once it’s dry, run a small amount of water through the sink. Keep a flashlight handy and watch closely for any signs of dripping. If the leak is slow, you may need to wait a few minutes for water to start pooling beneath the unit. Place a dry paper towel or piece of cardboard underneath to help detect smaller leaks.

Check the Bottom of the Unit

If water is dripping from the very bottom of the disposal, the problem is most likely due to worn-out internal seals or cracks in the casing. Unfortunately, these issues are not easily repairable, and a full replacement may be necessary. If the leak is small, you might be able to temporarily manage it with a sealant, but this is usually a short-term fix.

Inspect the Side Connections

If the leak appears to be coming from the side of the disposal, check the discharge pipe and sink flange for loose fittings or deteriorated seals. Sometimes, simply tightening a connection can stop the leak. If the leak persists, you may need to replace a worn-out gasket or reapply plumber’s putty to the sink flange to create a watertight seal.

Step-by-Step Guide to Fixing a Leaking Garbage Disposal

With so many possible causes of a garbage disposal leak, it’s best to break the repair process down based on where the leak is coming from. A leak from the bottom typically means internal components have failed, while a leak from the side or top could be due to loose plumbing connections or a worn-out sink flange. 

Fixing a Leak from the Bottom

1. Check for cracks or rust: Shine a flashlight under the sink and inspect your disposal. If you see rust or cracks, replacement is likely your only option.
2. Replace the internal seals: Some disposals allow you to replace the seals, but many are sealed units, meaning once the seals go, the whole unit needs to be replaced.
3. Consider replacing the garbage disposal: If the unit is old and leaking from the bottom, it’s usually more cost-effective to replace it rather than try to repair it.

Fixing a Leak from the Side or Plumbing Connections

1. Tighten the discharge pipe:  If the connection where the discharge pipe meets the disposal is loose, use a wrench to tighten it.
2. Replace the gaskets: If tightening doesn’t work, the rubber gasket may be worn out. Swap it for a new one.
3. Reapply plumber’s putty: If the leak is coming from the sink flange, remove the disposal, scrape off the old putty, and apply fresh putty before reinstalling.

Fixing a Leak from the Sink Flange

1. Loosen the mounting ring: Use a screwdriver to slightly loosen the mounting ring holding the disposal in place.
2. Apply fresh plumber’s putty: Scrape off the old putty and apply a fresh layer around the sink flange.
3. Retighten the mounting ring: Secure everything back into place and test for leaks.

Are Garbage Disposals Covered by a Home Warranty?

Most home warranty plans cover garbage disposals, but coverage can vary. If your disposal breaks down due to normal wear and tear, a home warranty will typically cover the cost of repairs or replacement. However, damage from improper use, lack of maintenance, or pre-existing issues may not be included. Check your specific policy to understand what’s covered and any service fee you might need to pay for a repair.

When to Replace Your Garbage Disposal

If your garbage disposal is leaking from the bottom due to age, rust, or seal failure, replacing it is often the best option. Most disposals last between 8-15 years, so if yours is approaching that range, it might be time for an upgrade. Newer models are often more efficient and quieter, making replacement a worthwhile investment.