Garbage Disposal Leaking: Locate and Fix

The first thing that comes to mind when noticing water under the kitchen sink is a drain problem. Few people think about garbage disposal. While plumbing issues are never fun, a garbage disposal leak is generally easy to fix. Before calling in a plumber, check the unit and see if you can solve the mishap yourself.

First, identify the garbage disposal leaking point: whether it’s the top, bottom, or side of the unit. Depending on that, you can fix the unit by retightening its connections or replacing the gaskets or the discharge pipe. If it leaks from the bottom, you likely need a new garbage disposal.

Garbage Disposal Leaking From Top

A garbage disposal unit leaking from the top is rarely faulty. The problem is in the sink and much easier to fix than you think.

Reason: Corroded or Loose Sink Flange

Kitchen sinks with garbage disposal devices miss the initial portion of the drain pipe. Instead, the shredder is attached directly to the flange. 

A gasket or plumber’s putty seals the connection between the garbage disposal and the sink’s flange. When the garbage disposal leaks from the top, you’re most likely dealing with a corroded flange or with a loose connection.

In the first case, you have to replace the flange; in the latter, you have to reseal the garbage disposal. 

Easy Fix: Replace the Flange and/or Reseal the Garbage Disposal

Step 1 – Turn water and power off 

Garbage disposals run on electricity, and it doesn’t take a rocket scientist to know that electricity and water don’t pair well. Thus, before doing anything else, turn off the water from the main and the electricity from the kitchen or main electric panel.

Step 2 – Lubricate the flange 

Rusted or corroded flanges are often stuck in position and very difficult to remove. Don’t try to force the flange out with a wrench or pliers because you could damage the garbage disposal, the pipes, or even break a porcelain kitchen sink.

Instead, lubricate it with some penetrative lubricant. Spray the product on the flange and let it soak for about 5-10 minutes. The penetrating oil will free up the flange and make it easier to remove.

Step 3 – Remove the flange

The flange should be relatively easy to remove once the penetrating oil has soaked in. Use a flathead screwdriver or a pair of pliers to pull it out from its slot.

Step 4 – Remove the old putty (or damaged gasket)

Most flanges are held in place with plumber’s putty, although some are sealed with gaskets. Use a putty knife to remove the old putty from around the flange and garbage disposal opening. If your disposal has a gasket, replace it with a new one if it is damaged.

Step 5 – Reseal and mount back

If the old flange is rusted or corroded, replace it with a new flange. Reseal with a new putty or a new gasket and mount the garbage disposal back. Turn on the electricity and water, then run the faucet and check for leaks.

Garbage Disposal Leaking From Side

Side leaks are as common as top leaks. The most common cause is a loose connection to the drain pipe or a worn-out gasket.

Reason: Loose Drain Lines 

Garbage disposals connect to the sink drain through the flange and to the P-trap through a lateral section of pipe connected to the unit’s side. The bottom houses the disposal chamber and isn’t connected to any line or pipe.

Side leaks happen because of a loose connection with the P-trap. Most garbage disposals are connected to the P-trap with screws and a rubber gasket. Fixing the issue means tightening or resealing the connection.

Easy Fix: Tighten or Reseal the Connections

Step 1 – Tighten the screws

More often than not, the garbage disposal leaks from the side because of a loose connection. Use an appropriate screwdriver (based on the type of fastener used) to tighten the screws. Open the tap and let the water flow for a few minutes, then check for leaks.

Step 2 – Replace the gasket

If the water still leaks, you’re likely dealing with a worn-out gasket. To replace it, turn off the water at the main and the electricity from the main panel. 

Unfasten the screws and take off the old gasket. Replace it with a similar gasket – you could either buy one for your specific garbage disposal model or take the gasket to a home improvement store and buy an identical one.

Step 3 – Tighten the connection 

Place the new gasket in the old gasket’s place and fasten the screws until tight. Turn on the water and electricity, then test for leaks.

Garbage Disposal Leaking From Bottom

Garbage disposal bottom leaks are almost always a sign of trouble. You may have no way to repair the unit and will need to replace it with a new one.

Reason: Busted Internal Seals or Damaged Unit

In addition to the external seals – with the sink’s flange and P-trap, garbage disposal units also feature a number of internal seals. These can break in time and are impossible to replace. Moreover, you could damage the unit while searching for stuff stored in the under-the-sink cabinet. The only thing you can do is replace the garbage disposal.

Easy Fix: Replace the Garbage Disposal Unit

Step 1 – Turn off the electricity and water

As explained above, water and electricity don’t mix. Turn them both off before working on your garbage disposal.

Step 2 – Unplug and remove the garbage disposal unit

Unplug the unit from the wall outlet it’s attached to, then unfasten the screws that connect it to the P-trap and remove the pipe. 

Hold the unit from underneath (or ask a helper to hold it), then remove as much plumber’s putty as possible from around the flange with a putty knife. If the flange is old and rusted, lubricate it with penetrating oil before attempting to remove it. Use a pair of pliers or flathead screwdriver to remove the flange.

Step 3 – Install the new garbage disposal unit under the sink 

Seal a new flange with the plumber’s putty, then install it at the bottom of your sink. Mount a new garbage disposal unit and seal the connection between the top of the unit and the flange with a rubber gasket or plumber’s putty.

Step 4 – Attach and seal the drain pipe

Attach the P-trap to the side of the garbage disposal unit by fastening the screws. Tighten as much as you can (without overdoing it) to create a tight seal between the disposal unit, rubber gasket, and pipe.

Step 5 – Plug in the unit and check for leaks

Plug the garbage disposal into the wall outlet and turn on the electricity and water. Run the faucet for five-ten minutes and inspect for leaks.

5 Tips To Prevent Garbage Disposal From Future Leaks

Most garbage disposal leaks are easy to fix, but if the unit gets to leak from the bottom, you’re faced with an expensive replacement. You can avoid this, though, by preventing future leaks. Here are a few tips to follow.

1. Run water after food disposal 

We all know we shouldn’t wash food scraps and grease down the kitchen sink, but we’re all guilty as charged. The problem is that congealed grease can damage the flange, seals and even deposit on the impeller’s blades, causing blockages and leaks. 

An easy way to prevent this is by flushing the sink and disposal unit with lots of cold water after you’ve disposed of scraps or grease down the kitchen sink drain.

2. Prevent dumping hard waste into the unit 

Garbage disposals can shred almost all kinds of foods and food waste into tiny pieces, but they can’t deal with hard waste like bones, hard shellfish parts, or corn kernels. These scraps can damage the blades and internal gaskets. Moreover, they can clog the drain. Thus, you should avoid throwing these things into your disposal unit. 

3. Avoid dumping starchy foods down the sink drain

Similar to fats and grease, starchy foods can stick to the various parts of your disposal unit and harden on them. While congealed grease could melt under hot water, hardened starch is a pain to remove – and could sometimes lead to irreparable damage. 

4. Flush small portions at a time

Garbage disposal units can deal with most food scraps, but you should divide larger waste into smaller portions. Put as little trash as possible into the sink and let the disposal shred everything into tiny pieces before feeding it another portion.

Larger scraps, such as melon skins and large chunks of food, should go into the compost pile or dustbin rather than the garbage disposal.

5. Perform regular checkups 

Lastly, don’t forget to run maintenance and check the unit regularly. In this way, you can spot even the slightest leaks right away and intervene promptly.

Frequently Asked Questions

As you’ve read, garbage disposal leaks are easy to treat – as long as they don’t come from the unit’s bottom. Do you still have questions? Check out the answers below.

How much does it cost to fix leaking garbage disposal?

You can expect to pay around $250-$400, including materials and labor, on average, if you have to replace the unit. For smaller fixes, plumbers charge about $80 per hour on average. 

Can you run the dishwasher if garbage disposal is leaking?

You could run the dishwasher if the garbage disposal is leaking, as long as the dishwasher is connected to the drain pipe rather than the disposal unit. If it is connected to the disposal unit, you may want to wait until you fix the leak.

Can a leaking InSinkErator be repaired?

Leaking InSinkErators can be fixed if the leak occurs at a joint, as explained above. Faulty units that leak should be replaced, though.

To End

Leaking garbage disposal units are a cause of distress, but they can cost you next to nothing to fix if the leak doesn’t happen because of a faulty unit. However, you should replace the unit if it leaks from the bottom – attempting to fix it could end in greater disaster if water and electricity manage to mix. 

Where is your garbage disposal unit leaking from? Will you attempt to fix it yourself or call a plumber? Tell us in a comment.

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