Garbage disposal leaking: Common causes and how to fix them

Your garbage disposal efficiently handles food waste and keeps your sink flowing smoothly. But when it starts leaking, that convenience quickly turns into a headache. Suddenly, you have water pooling under the sink, foul odors, and potential damage to your cabinets. 

Ignoring the issue will not make it disappear; it will only worsen. The good news is that most garbage disposal leaks are fixable and you can do it on your own. 

In this post, we break down the common causes of garbage disposal leaking, how to fix them, and measures you can take to prevent them from reoccurring. But first, what signs should you look out for?

Signs your garbage disposal is leaking

You might have a leak if you notice water pooling under your sink or hear dripping sounds when the garbage disposal is running. Here are some common signs to look out for:

• Water pooling under the sink could indicate a crack, loose seal, or faulty connections.
• Dampness, swollen or warped wood, or mold around the disposal is a red flag.
• Persistent foul odors of rotting food, even after cleaning, signal a leak.
• Dripping noises after running the disposal might point to a crack in the unit or a loose pipe connection.
• Visible rust or corrosion around the disposal.
• Sluggish performance may result from water damage affecting the motor or electrical components.

If a garbage disposal continues to leak without proper repair, it can cause severe damage. Water can weaken the cabinet base, promote mold growth, and even pose electrical hazards. The sooner you address the problem, the less likely you will face major repairs or replacements.

Why is my garbage disposal leaking?

A leaky garbage disposal is caused by either internal wear and tear of seals, loose screws, or misaligned fittings. Let's look at these common reasons in detail.

Internal damage

If your garbage disposal is leaking at the bottom, it’s likely due to internal wear and tear. Over time, the unit’s internal seals can deteriorate, allowing water to seep out. Since these seals are deep within the garbage disposal, they can’t be easily repaired, and you will need a replacement.

Worn or damaged seals

Leaks from the top of the disposal happen when the rubber or plumber’s putty seal connecting the disposal to the sink flange wears out. To check for this issue, unplug the garbage disposal and feel around the top for moisture. If you notice water pooling around the seal, it is either worn or damaged.

Loose or improperly installed connections

Loose or improperly installed connections can cause leaks from the side of the disposal. This issue may stem from loose screws, misaligned fittings, or degraded rubber seals on the dishwasher hose or drain pipe. Properly securing these connections will prevent leaks.

How to fix a leaking garbage disposal

Fixing a leaking disposal depends on where the leak is coming from. Here’s how to address each issue based on the source of the leak.

Leaking from the top

If your garbage disposal leaks from the top, it’s likely due to a worn-out sink flange seal or deteriorated plumber’s putty.

Here’s how to fix it:

• Unplug the disposal or turn off the breaker to ensure safety.
• Loosen the mounting ring and gently lower the disposal unit.
• Scrape off the old plumber’s putty or worn rubber gasket from the sink flange.
• Roll a new bead of the plumber’s putty and press it around the sink flange.
• Secure the flange back in place, reattach the disposal, and tighten the mounting ring.
• Run water and test for leaks.

Leaking from the side

Side leaking garbage disposals mainly occur at the dishwasher connection or drain pipe due to loose screws, worn gaskets, or misaligned fittings. Here’s how to fix it:

• Tighten the screws where the drain pipe connects to the disposal.
• Check for cracks or wear in the rubber gaskets and replace them if needed.
• Replace the dishwasher hose if it’s brittle.
• Run water and turn on the disposal to check for leaks.

Can you fix a garbage disposal leaking from the bottom?

A garbage disposal leaking from the bottom usually means the internal seals of the garbage disposal have worn out due to age or prolonged use. Unlike leaks from the top or sides, a bottom leak is often a sign that the disposal has reached the end of its lifespan.

Applying waterproof sealants can temporarily fix the problem, but it won’t last, especially if the garbage disposal is over 8 to 10 years old or showing signs of frequent clogs. The best solution is to replace the garbage disposal to prevent repeated issues.

Cracked housing

If your garbage disposal’s body is cracked, water will leak out no matter how well the seals and connections are maintained. The only solution for this is to install a new garbage disposal unit.

Clogged drain causing pressure buildup

A clogged or slow-draining sink can create pressure in the pipes, forcing water to escape from weak spots. Try plunging the sink to remove minor blockages. Next, remove and clean the P-trap (the curved pipe under the sink) to clear out debris. If that doesn’t work or the clog is deep in the pipe, use a drain snake to break it up.

You can also use essential household ingredients like vinegar and baking soda to clean your sink drain. Mix 1 cup of water, 1 cup of white vinegar, and 1 cup of baking soda in a bowl. Once the mixture starts fizzing, pour it into the sink drain and cover it with the plug. Leave it to sit for 15 minutes, and then pour boiling water down the drain.

Preventing future garbage disposal leaks

Regular maintenance and proper use are essential to extend the life of your garbage disposal and prevent future leaks. Here are some key steps to keep your disposal in top shape:

• Always run cold water while using the disposal to solidify grease and flush out food particles. Hot water can melt fats, causing them to solidify deeper in the pipes and create blockages.
• Tighten drain connections, dishwasher hose, and mounting bolts periodically to prevent slow leaks.
• Clean the disposal weekly with ice cubes, rock salt, and lemon wedges to remove buildup and odors.
• Avoid bones, fruit pits, corn husks, and celery fibers that can damage the blades and clog the drain.
• Don’t pour grease or oils down the drain; they can solidify and cause blockages.
• Cut large items into smaller pieces to prevent motor strain and potential cracks.
• Check for early warning signs. Slow draining could indicate buildup in the pipes. Unusual noises or vibrations could mean loose hardware or internal damage.

Fixing leaks early prevents bigger issues

Even a small leak can lead to water pooling under the sink, unpleasant odors, weakened cabinet bases, mold growth, and structural damage over time. If left unaddressed, it can also pose an electrical hazard. 

Hence, regular maintenance is key to avoiding these issues. Periodically check for loose connections, inspect for moisture, and clean the garbage disposal with ice, rock salt, and lemon. 

By taking these precautions and maintaining your garbage disposal well, you can extend its lifespan, improve kitchen hygiene, and save money on costly repairs or replacements.

FAQs

Do I need a plumber to fix a leaking garbage disposal?

You can fix some garbage disposal leaks yourself, especially if they’re caused by loose connections or a worn-out flange. Do it yourself by tightening the screws and resealing the sink flange. However, if you notice persistent leaks or don’t know where the leak is coming from, it’s best to call a plumber.

How can I identify the source of the leak?

Run water through the garbage disposal and look for drips, pooling, or moisture around the top, sides, or bottom. To pinpoint smaller leaks, use your hand to feel for moisture around the sink flange or drain connection. Alternatively, wrap a dry paper towel around suspected leak points and check for wet spots.

Can a garbage disposal leak be fixed without replacing it?

Yes, a garbage disposal leak can be fixed, depending on its source. If it’s from the top or side, change the sink flange, reseal with the plumber’s putty, or tighten drain lines. However, if it is from the bottom, it indicates internal seal failure or cracks in the housing, which require a full replacement.