Leaking Garbage Disposal? Here’s How to Fix It

Apr 30, 2021 | Home Repair, Plumbing

Got a leaking garbage disposal? It’s a real pain. It drips into the cupboard under your sink and causes untold damage. If left unchecked, it could destroy the cabinet and allow mold and mildew to grow. 

If you spot your garbage disposal leaking, the good news is it is easy to fix. But what could be the root of the problem?

Let’s take a look at the common issues that cause your garbage disposal to leak.

1. Worn Out Gaskets

One of the first things you should check is the gasket if you spot water dripping from your garbage disposal. The gasket sits between the flange and the rubber seal. The two most common reasons why your gasket fails are over and underuse.

If your garbage disposal gets a lot of use, the gaskets wear out and start to drip. Likewise, if you rarely switch it on, the gasket dries out and becomes brittle. 

How to Fix

  • Pull out the plug by detaching the drain, and if your disposer connects with the dishwasher, remove the connecting hose.
  • Grip the sides of the mounting nuts and slowly twist the unit clockwise. As it moves, it unlocks from the housing and falls forward. Lift it out so that the gasket is exposed.
  • Swap the old gasket for the new one, taking care to position it exactly where the old one was. Also, make sure the gasket sits completely flat. 
  • Now place the garbage disposal unit back into place in the sink. Before installing the disposer, make sure that the gasket creates a watertight seal.
  • Twist the disposer counterclockwise to lock it in place and reattach the drain and dishwasher hose. 

2. Leaky Sink Flange

The flange sits at the highest point of the garbage disposal, where it joins with the sink and drain. The flange prevents dirt and grime build-up, but over time can fall foul to overuse. If water is leaking from the flange, you may have a weak seal or loose mounting bolts. 

If the seal is compromised, consider replacing the plumber’s putty. You can do this by unscrewing the bolts until a gap appears. Place the sealant inside the opening, so it seals when you tighten the bolts. 

If water still leaks from the top, here are the steps you can take to fix it. 

How to Fix

  • Take out the screws attached to the main drain pipe and remove the dishwasher hose by taking off the screws that secure the clip to the disposer. 
  • Now remove the mounting ring that holds the disposer to the housing under the sink. Lift out the garbage disposal and place it to one side. 
  • Take out the bolts in the mounting assembly with a wrench. 
  • Now raise the flange from the sink and remove the old putty, making sure to wipe away any debris with a damp cloth. 
  • Grab some new putty and roll it out in a thin sausage shape so that it wraps around the circumference of the flange.
  • Place the putty around the outside edge of the flange and slot it back in place in the sink drain hole. 
  • Reinstall the mounting ring and assembly, and tighten the screws. Next, install the dishwasher hose, drain pipe, and disposal unit.

3. Loose Drain Lines

Check the connection where the drain lines meet the garbage disposal. You should see a thick pipe called the sewer disposal line and a thin pipe, which attaches to your dishwasher. 

How to Fix

  • If you spot leaks, grab a screwdriver and tighten the clamp that holds the garbage disposal to the dishwasher.
  • Also, tighten the screws on the dishwasher disposal line. 
  • While you are there, inspect for breaks and tears. Over time, fittings age and need replacing. You are best calling a professional if you need to replace drain lines. 

4. Loose Seals or Pipes

You need to check under the sink for the loose seals and pipes. Feel around the joints for water. It’s a common occurrence because garbage disposal units are located in cupboards beneath the sink and frequently get knocked when you store items. 

This causes the pipes to work loose. 

How to Fix

  • Check all the mounting bolts are tight and the seals are free from drips. 
  • Grab a screwdriver and systematically work your way around all the screws, giving them that extra half a turn to make sure they are watertight. 
  • Remove some of the items stored in the cupboard and place them elsewhere. It should avoid a repeat of the problem. 

5. Bad Dishwasher Connection

You might be wondering why the dishwasher connects to the garbage disposal, but your dishwasher drains food waste every time you wash dirty dishes. 

The hoses work loose over time or start to perish. 

How to Fix

  • Repeat the same procedure from the last step and grab a screwdriver to tighten all the screws that attach the drain line to the dishwasher.
  • Inspect the pipes for wear and tear or cracks. If you spot one, you will need to source a replacement. 
  • Remove the old pipe by loosening the clips that hold it to the drain hose. 
  • Swap it for the new hose, and tighten the screws, so it is secure. 

6. Split or Cracked Body

Some issues are more serious. A split or cracked housing of the actual disposer could mean you need to replace the whole unit. While it is a fairly simple process, it does cost more money. 

To check you have a split housing, grab a flashlight and examine the exterior closely. If you see a crack or feel water, it’s time to act. If you can patch it, but the problem will come back eventually. 

How to Fix

  • Disconnect the power from the wall. 
  • Disconnect the dishwasher drain line and then grab a hammer to punch out the knockout. The last thing you want is the disposal to grind that and get blocked or broken. 
  • Support the weight of the housing using a wooden board resting on something high enough it sits directly under the disposal unit.  Some units can weigh up to 15 pounds. A can of paint usually works. 
  • Now unhook all the attachments using a screwdriver to loosen the clips of the hoses. 
  • If you are replacing just the housing beneath the sink, there is no need to remove the mounting bracket or the flange. 
  • Offer up the new unit so it rests on the platform to take the weight. Screw it into the mounting clip clockwise to create a seal with the flange. You might need pliers or an adjustable wrench for this. 
  • Now tighten the bolts until it is watertight. 
  • Reattach all the hoses and drain lines using a screwdriver to screw the clips shut. 

7. Leaking Reset Button

If your reset button is leaking, you have a couple of options: get a new reset button from the manufacturer or seek professional advice. Trying to repair it is a quick fix, but one that comes back to haunt you down the line. 

How to Fix

  • Unless you know garbage disposals and are comfortable replacing a faulty switch, you should always seek the advice of a professional for this job, especially if your unit is new and still under warranty.

 8. Loose or Damaged Discharge Pipe

Once you’ve exhausted all the potential issues above and you still have a leak, check that the discharge pipe has no damage or worked loose. 

Again, damage occurs when it gets knocked every time you place detergent and other items in the cupboard under the sink where it lives. 

How to Fix

  • Check the clip is loose by screwing it tighter with a screwdriver. If the pipe still comes free with gentle pressure, it could be the seals. 
  • To change the seals, remove the drain line by loosening the clip and detaching the pipe. 
  • Change the seal and reattach by tightening the flange. 
  • Test it to see if it is solidly in place and no water leaks out. 

How to Find Where the Garbage Disposal Is Leaking

Start by drying the area under the sink, ensuring that all the joints and pipes are completely free of water. 

Now plug the sink drain where it leads to the garbage disposal. Fill the sink with water. Take a look at the underside of the disposer to see if the water is dripping. If it is, you may have deteriorating seals around the flange.

Also, watch for water droplets around the disposal unit or where the pipes and joints are. If the dishwasher hose is leaking, you might have perished lines that need replacing. 

It could also be a result of the flanges needing tightening. If that is the case, it is the easiest fix. If the leak springs from the drain line, it could be you need a new seal where it connects with the drain spout on the garbage disposer. 

Tips for Preventing Garbage Disposal Leaking

There are ways you can minimize the chances of damage to your garbage disposal. By changing your habits and the types of foods you dump in the disposal, you can preserve its lifespan for longer. 

Avoid Hard Foods

One of the best ways to avoid issues with your garbage disposal is to regulate what foodstuffs you dump. Hard foods like bones, shellfish parts, and corn kernels place an enormous strain on your unit, causing it to malfunction.

Consult the manual to see what capabilities your garbage disposal can handle. If you have a high-end model, it may tackle tougher foods better than a budget model. 

If you are in doubt, dump the hard foods in the trash or the compost pile for the garden. 

Avoid Fibrous or Starchy Foods

Foods like celery, fruit seeds, banana skins, and onion skins have a fibrous quality. They are also high in starch. The fibers twist around the mechanism inside the disposer, while the starch can set hard. 

You could try cutting them into smaller pieces to decrease any impact they may have, but your best bet is to toss them in the trash. Also, avoid grinding eggshells, as these can clog the garbage disposal. 

Cut Food Waste Into Tiny Portions

The smaller you cut up the waste, the easier the disposal will chew through it. Smaller chunks help to do some of the disposer’s work and so allows it to make light work of your foodstuff. 

Again, if you have a lot of food waste, rather than spending hours cutting it up, just scrape it into your compost pile and put it to better use. 

Use Water

As the food drops into your garbage disposal, flush it down with cold water. Leave the faucet running for 30 to 40 seconds to aid its smooth passage. The cold water keeps the unit from heating and washes down any food that might cling to the pipework. 

Keep It Clean

Wipe the grinder with kitchen paper to remove grime build-up. Only do this with the power disconnected. Alternatively, toss some ice cubes in to give everything a thorough clean. You could also try lemon juice or vinegar to keep it clean and deodorized. 

You can tell when your garbage disposal needs some TLC when you start to get bad odors. 

Garbage Disposal Leaking FAQ

Why is water leaking from the bottom of my garbage disposal?

The most common cause of water leaking from the base of your garbage disposal is a faulty internal seal. The seal protects the motor and it prevents the unit from leaking water. 

Time and wear and tear cause seals to perish, which allows water to seep out of the bottom. 

What do you do when your garbage disposal leaks from the bottom?

If you are attempting to fix the leak rather than replace the whole unit, you will need to detach the disposal, strip the housing away from the contained unit and locate the internal seals. 

Replacing the seals with new ones is crucial to preventing further drips. However, most disposal units are designed as throw-away items, and so when the seals fail, it is easier to invest in a new garbage disposal unit. 

That way, you have the peace of mind that all of the internal components are new and nothing else is likely to fail. 

Can you run the dishwasher if the garbage disposal is leaking?

You can still run your dishwasher if the garbage disposal is leaking. It won’t send any dirty water into your dishwasher, but it will cause the disposer to leak more with the excess water.

How much does it cost to fix a leaking garbage disposal?

It all depends on the type of garbage disposal you own and the rates charged by the plumber. So, you could be looking at a cost ranging between $250 to $400. 

Don’t Throw Money Down The Drain

It’s what you risk doing if your garbage disposal leaks and you call in the professionals. Always take the time to do your research and try to identify the issue first. 

It could save you a lot of money on expensive repairs, and you just might be able to fix it yourself. 


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