Why Does It Smell Under My Kitchen Sink?

Why Does It Smell Under My Kitchen Sink

The kitchen is supposed to be filled with delicious, mouth-watering smells swirling through the air. However, your kitchen might smell rotting food, musty, or even sewage when things go wrong. These nasty odors put a damper on the motivation to prep tantalizing meals in your kitchen, so it’s about time you fix that. 

For the most part, three common culprits cause nasty odors in your kitchen. Luckily, correcting the problem is usually quick and easy, something most homeowners can handle without calling a plumber. So, before you reach for your phone to call your plumber on speed dial, give these methods a go. 

What Causes Odors Under A Kitchen Sink?

Odor under your kitchen sink can happen for a few reasons, some more common than others. These are the top three reasons why the space under your kitchen sink smells terrible:

Water Damage

With water lines, drain pipes, and dishwasher/garbage disposal hookups interconnected beneath your sink, there are plenty of chances for a leak. All it takes is a steady drip from a poorly connected joint in the plumbing or a pinhole leak in the dishwasher line. 

If you don’t notice the leak immediately, problems will begin to develop in the cabinet beneath the sink. You’ll probably notice an unpleasant musty smell wafting from the cabinet when you open it, and you might even see mold growing in damp areas of the wood. 

This can be the root cause of the unpleasant smell, especially if the odor specifically smells damp or musty. 

P-Trap Issues

The U-shaped section of pipe beneath your sink plays a vital role in preventing horrible smells from invading your kitchen. If this section of pipe (known as the P-trap) malfunctions, sewer gases can come up through the drain. 

In some cases, you might notice the smell under the sink and around the drain, although you might have a tough time pinpointing the exact place the odor is coming from. P-traps prevent sewage gases from coming back up and out of your drains by keeping water in the trap. 

The bend in the pipe holds water, effectively halting the movement of the gases up the pipe. You might notice that your kitchen sink smells suspiciously like sewage after a long trip away from home. This can happen as a result of the water in the trap evaporating. 

Debris Buildup In The Garbage Disposal

Although garbage disposals are a handy addition to nearly any kitchen, they regularly require proper care and maintenance. Without regular cleaning, food particles can build up in the disposal’s canister. When this happens, the food begins to decompose, causing awful smells in your kitchen.

In some scenarios, you might notice the smell above the sink, near the drain, or you might notice the smell beneath the sink. Either way, it could be the result of rotting food. So, if the scent overtaking your kitchen and sink cabinet smells like rotting foods, this could be the issue. 

How Do I Get Rid Of The Smell Under My Kitchen Sink?

To get rid of the awful smell under your kitchen sink, you’ll need to isolate the problem. Generally, the issue is due to one of the culprits we discussed above. On rarer occasions, it can result from a more serious issue, like broken plumbing. 

However, before you jump to conclusions and automatically assume the worst, try to determine what is causing the smell. Rotting food, sewage, and mustiness smell considerably different, so differentiating between the three common culprits is pretty simple. 

Once you isolate the problem, here’s how to fix it. If you can’t figure out the issue, try these three solutions to see if they correct the problem. 

Fill The P-Trap

If you’ve been gone from home for a few weeks, you might notice a particularly pungent sewer odor wafting from the drains in your home. The smell might seem to emanate from the cabinet, although it often overtakes the entire space. 

Luckily, correcting an empty P-trap is easy. Simply run the water in the sink for about 30 seconds, which will fill the P-trap. If the problem were due to the water evaporating, this would fix your issue in seconds. 

Look For Mold And Water Damage

Sometimes, the P-trap might not be the issue. If the odor smells mustier than like sewage, check beneath the cabinet for a leak. This could be the problem, especially if you recently installed a new faucet, switched out your garbage disposal, or had to disconnect the plumbing for some reason. 

A poorly tightened connection can leak, spilling water into the cabinet below. If left unchecked, the water damage can create a musty odor and be the ideal breeding ground for mold colonies. So, take a peek in the cabinet beneath the sink. 

Look at all parts of the cabinet’s interior – the doors, sides, back, and bottom. Check for dark areas in the wood, as this can indicate water damage. Additionally, look for bubbles on the surface of the cabinet, as this can also point to water damage. 

While you’re down there, look for greyish-green, black, or white patches on the surface of the cabinet. This can indicate the presence of mold, which can be dangerous to inhale. If you notice mold, close the doors immediately and collect the proper gear to tackle the problem. 

If you find mold, follow our guide for safely killing and removing the colonies here

If there isn’t any visible mold, you might have caught the problem quickly enough. However, you’ll need to dry out the cabinet thoroughly. So, remove everything from the inside of the cabinet, then open both cabinet doors. Set a small box fan (if you have one) outside the cabinet to help accelerate the drying process. 

Wait until the inside of the cabinet is completely dry before replacing the items. Additionally, make sure to find and repair the leaking area before proceeding, or you’ll be back to square one when you start using the sink again. 

In some scenarios, the water damage might be severe. Sometimes, this might require you to replace the cabinet altogether, especially if it’s too far gone to repair. 

Clean The Garbage Disposal

The garbage disposal is the last common culprit of a smelly sink cabinet and drain. Many homeowners use their garbage disposal daily to grind food scraps, tossing fruit trimmings, vegetable scraps, and small amounts of leftovers down the drain.

While it’s a convenient way to dispose of extra scraps, garbage disposals require quite a bit of maintenance. On top of that, certain food items should never go into your garbage disposal. Without a proper cleaning schedule or only grinding disposal-safe foods, your garbage disposal might begin to smell. 

This can cause your sink cabinet and drain to smell absolutely terrible. Food particles can get caught in the canister, remaining stuck there after you turn off the appliance. When this happens, the food begins to decompose, causing nasty odors in your kitchen. 

To get rid of this problem, you’ll need to clear the clog (if there is one), then clean the unit. We have a detailed guide on both parts of this process. For an easy-to-follow guide on tackling tough clogs, click here
Once you finish that part (as needed), click here for our cleaning guide. We’ll walk you through cleaning the disposal, which is a quick process that usually requires baking soda, vinegar, and citrus peels (for a fresh scent).