Garbage Disposal P-Trap Leaking (Cause and Quick Fix)

When the garbage P-trap leaks, chances are you will only find out after some time, sometimes several days after it has started leaking. You will only see the area under garbage disposal begin to get soggy, sometimes getting smelly.

This stems from the fact that the p-trap has the least pressure, hence the minimal leaking drops of fluid and water. 

While there are several causes of the p-trap leaks, the fixing tips match up to the task. Before that, though;

What is a P-Trap?

A p-trap refers to the u-shaped part of a garbage disposal drain. It is also in other drains, such as the sink, bathroom, and toilet. The p-trap traps water whenever there is no pressure to ensure that gases down the sewer don’t get back to the house.

The p-trap rarely leaks, but this does not mean it doesn’t. For this reason, let’s get on to why it leaks and a complete guide on how to correct the mess;

What Causes garbage disposal p-trap to leak?

We have a simplified table on the causes of p-trap leaks;

Causes of P-Trap Leaks
Improper fit
Overtightened bolts
Under Tightened bolts
Faulty washers
Corrosion (for metallic p-traps)
Cracked p-trap pipe

Improper Fit

If you have p-trap parts that don’t fit well into each other, especially from different brands, this may cause the p-trap leak. In most cases, the part going into the more significant part is relatively small, fitting, hence leaking.

Overtightened Bolts

A trap with over-tightened bolts can have the trap design misaligned. Moreover, the overtightened nuts cause the trap material to crack under pressure.

While it may seem far-fetched, overtightened bolts may cause the need to replace the p-trap to correct the leaking.

Under tightened bolts

Tightening bolts properly is always crucial to preventing leaking. However, even as you avoid overtightening the nuts, ensure that you don’t lean on the other extreme and under tighten them.

If you don’t tighten the nuts enough, they will leave space that gives a chance to leak.

Faulty Washers

If the washers in the p-trap are too dry or get rusty, the result could be a p-trap leak under your drainage. Other than that, the washers could have been misaligned during the installation. The misalignment also causes a leak.


Metal traps and bolts may rust over time. The corrosion leads to cracks, which in turn lead to p-trap leaks.

Cracked P-Trap Pipe

A cracked p-trap leaking is almost obvious. For whatever reason

How to Know If P-Trap is Bad?

As mentioned earlier, the p-trap could leak for days and still go unnoticed. On the other hand, every leak underneath the sink does not imply that the p-trap is the leaking section. For this reason, let’s take a look at how you would recognize a p-trap leaking;

  • The cabinets or area under the sink will appear soggy or slippery.
  • In more extreme cases, you will hear a dripping sound under the sink.
  • When singling out the leaking area, wipe the whole drain area. Then, put a piece of newspaper around the p-trap if you guess it is the cause of the leak. The newspaper will be wet and soggy if you are right.

Get on to the fixing process once you are sure that the p-trap is the problem behind the leaking.

Can A Clogged P-Trap Cause a Leak?

Not really. As long as the fittings on the p-trap are correct, a clog should not cause a leak. On the contrary, water and garbage will not flow through the p-trap. However, if the p-trap has a misalignment, the clogging squeezes it to the edge and causes a leak.

How to Fix a Leaking P-Trap

With basic plumbing skills, you can fix the leaking p-trap yourself. The correction measures may include correcting the alignment of the p-trap parts or replacing them altogether. 

Either way, you may be forced to remove the p-trap first. But don’t fret, as we have a way around that as well;

How to Remove the Garbage Disposal Drain P-Trap?

First, ensure that the water tap is not running from the sink to jeopardize your task. Then, start removing the garbage disposal drain pipe.

While there are times when hand removal is successful, having a drain pipe nut wrench always eases the task. Use the wrench to loosen the nut between the tailpiece and the p-trap, then remove the nut by hand. 

There is also another nut at the mid trap, which you will also use your wrench to loosen and remove. Finally, loosen the nut lying on the trap arm, and you will have the p-trap free for removal.

Fixing a Leaking P-Trap

Remember you already identified the cause of the p-trap leak? You can fix the following without the need for replacement;

  • If the p-trap has misaligned parts, align the parts correctly and watch this out when putting the trap back in place.
  • When the challenge is loosened or overtightened nuts, you can always tighten the nuts enough to prevent further leakage.

However, there are situations where you have no option but to replace the p-trap parts;

  • Replace a cracked trap part to deal with the leaking. However, if the crack is tiny, you can also use a trap sealant to prevent the leak for the time being.
  • Corroded pipes and nuts require replacement as the ultimate solution.

When replacing u-trap sections, ensure that you use parts from the same company. Then, if you can’t get them, you can try companies with similar parts that fit into your older trap parts.

Here is a summary table for p-trap leaking solutions;

Causes of P-trap LeaksHow to Fix the P-Trap Leaks
Improper fitReplacement 
Overtightened boltsLoosening enough
Under Tightened boltsTightening enough
Faulty washersReplacement, correcting alignment
Corrosion (for metallic p-traps)Replacement 
Cracked p-trap pipeReplacement 

What is the Best Sealant for Leaking Pipes?

I prefer a common kitchen pipe sealant such as this putty stick, suitable for all pipes, including plastic, metal, rubber, marble, fiberglass porcelain. It keeps the pipe from leaking, and while it can be a lasting solution, it is an intermediate one for larger cracks.

Sealants are inexpensive, and the only thing you have to look for in a suitable pipe sealant is performance. As long as it sticks perfectly and is durable, it will serve its purpose.

Can Overtightening the P-Trap Stop the Leak?

No, it can’t. On the contrary, overtightening the p-trap nuts could be the cause of the leak. Too much tightening cause cracks on the pipes, which in turn cannot hold water efficiently.

On the other hand, a loose nut fitting can cause a leak. In this case, you will need to tighten the p-trap more. However, it shouldn’t go beyond the typical tightening.

Should I Call a Professional When My Garbage Disposal P-Trap Leaks?

If you don’t have the tools, confidence, or time to deal with the leaking p-trap, you can always get a professional to do it for you at a cost.

However, if you love taking care of stuff yourself and learning more DIY ideas, this guide is for you.

Whichever way you prefer, the choice is personal. There is no shame in getting a professional, neither is there any harm in trying things that don’t necessarily need expertise.

Parting Shot

Garbage disposal p-trap helps us by blocking gases that go down the sewer not to affect the house. However, because garbage and water get in through the disposal trap, a leak smells and a damp site underneath the sink.

Nevertheless, whenever you have a solution to a challenge, it ceases to be a problem. And, the best news is that you can undertake the fixing of the p-trap without external help.

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