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“Why Does My Sink Smell?” 5 Common Reasons For Smelly Drains

smelly drains
Fix December 30, 2019
Arthur Brodskiy
Arthur Brodskiy

Rotten eggs. Sulfur. Mildew. All smells you don’t want to associate with your sinks or garbage disposal. But the reality is, smelly drains are something most homeowners are going to have to face at some point, especially if you have bad plumbing habits. Over time, drains have a tendency to collect buildup and give off some not-so-pleasant smells. In this article, we’ll outline some causes for smelly drains and give you some tactics to knock out those offensive odors. 


1. Garbage Disposal Blades


Garbage disposals do a great job at breaking up food waste so it can work its way through our pipes. But over time, some of that food matter can accumulate on the disposal blades. Eventually all that residue and grease can turn into a smelly mess. Here’s a couple of ways you can clean your garbage disposal blades with simple household ingredients:


Cleaning Method 1: Kosher Salt and Ice Cubes

    1. Dump an entire tray of ice cubes into the garbage disposal. 
    2. Slowly pour one cup of kosher salt into the garbage disposal.
    3. Turn on the garbage disposal. 
    4. Turn on the kitchen sink tap as cold as it will go.
    5. Let the garbage disposal and tap run for one minute. 

Cleaning Method 2: Baking Soda and Vinegar

    1. Pour one half cup of baking soda into the garbage disposal. 
    2. Carefully pour one half cup of vinegar into the garbage disposal. 
    3. Use a plug to block the drain and allow baking soda and vinegar mixture to sit for ten minutes. 
    4. Turn on the garbage disposal and run hot water through it for two minutes. 

Manually Cleaning Garbage Disposal Blades

If the two cleaning methods didn’t seem to do the trick, you can always manually scrub away any residue on your garbage disposal blades. A pair of rubber cleaning gloves, some dish soap and a sponge or dish wand is all you need. 

A little word of warning, though: Cut off the garbage disposal’s power source before you put your hands down the drain. This might mean located the proper circuit in your circuit box. Don’t just rely on the switch on the wall.


2. Clogged Or Dirty Drains


why your bathroom sink smells


If that bad smell is coming from another sink or tub drain in your home, you probably have some buildup or even a slight clog that’s causing it. Hair, grease and soap scum can cause stick to pipe walls and encourage bacteria growth. If you tackle a clog early enough, you should be able to take care of it without having to call a plumber. 

Cleaning Method 1: Hot Water and Dish Soap

    1. Heat up a quart of water on the stove top or in an electric kettle. Get it very hot, but not boiling. 
    2. Add two ounces of dish soap and stir.
    3. Slowly pour the mixture down the drain. 
    4. Follow up with some cold tap water.

Cleaning Method 2: Hot Vinegar

    1. Heat up a quart of vinegar. Just like the water in the first method, you want to get it hot but not quite boiling.
    2. Slowly pour half the vinegar down the drain. Let it sit for two minutes
    3. Run cold tap water for one minute.
    4. Pour the rest of the vinegar down the drain. 

Cleaning Method 3: Manual Removal With Drain Snake

If the dish soap and vinegar both didn’t solve your clog problem, it’s time to bring out the big guns: a screwdriver and a drain snake. The first thing you’ll need to do is remove the drain cover from the drain. If it’s a tub, you should be able to easily remove it with a flathead or phillips-head screwdriver. For a bathroom sink, you’ll have to remove the stopper by disconnecting it from under the sink. 

Once the cover or stopper is out of the way, simply feed the drain snake into the drain pipe until you feel the obstruction. Twist the snake around and you should be able to either dislodge it or hook into it and pull it out. After you’ve cleared the obstruction, replace the cover or stopper.

3. Buildup In P-Trap


The p-trap is the u-shaped section of pipe located directly under your sinks. Over time, a p-trap in a heavily used sink can get gunked up with hair, grease and other debris. That can lead to clogs, fruit flies and eventually some pretty nasty smells. P-traps are easy to remove and clean:


  1. Look under the drain and locate the lock nuts on each side of the “U.”
  2. Place a bucket underneath the p-trap.
  3. Unscrew the lock nuts.
  4. Remove the p-trap. Water from the p-trap and adjacent pipes will drain into the bucket. 
  5. Manually clean the p-trap and rinse it out in another sink.
  6. Reattach the p-trap.

4. Dry P-Trap


Sometimes the issue with p-traps has nothing to do with buildup. It’s because they’re totally dry. To understand why this is an issue, it helps to know the real purpose of p-traps.


Every drain pipe in your home feeds into a sewer line. The p-trap’s “U” shape is designed to keep some water trapped inside, which creates a barrier between your drain and the sewer line. Without this water barrier, gas and odor from the sewer line would come right out of your drains. 


So if you ever smell sulfur or rotten eggs coming from your drains, the culprit is almost definitely a dry p-trap. Sometimes tubs or sinks that get used infrequently (in a guest bathroom, for example) can have dry p-traps because the water eventually evaporates from them. If that’s the case, just running those fixtures for a minute should solve your problem. 


If you have a dry p-trap under a fixture that gets regular use, you could have a leak in the p-trap. Place a bucket under the p-trap and run the fixture. If you see any water leaking out, you’ll know you either have to replace the p-trap or get new washers. 


Dry p-traps without an apparent leak are a sign that you have a clogged plumbing vent.   


5. Clogged Plumbing Vent


rotten eggs smell kitchen sink


Plumbing vents are the vertical pipes that run from your sewer system up to the roof of your home. They keep the sewer smell out of your home and help keep your p-traps from drying up.


If you don’t have a working plumbing vent, the pressure in your drains becomes unbalanced on either side of the p-trap, leading to the p-trap drying up.


Plumbing vents can get clogged with leaves, sticks and even bird’s nests. Since plumbing vents run the entire vertical length of your home, dealing with a clog might be a job for a professional plumber. Having a vent cap installed can help prevent future clogs.




Most smelly drain problems can be tackled pretty easily with common household items and a little elbow grease. Cleaning out your garbage disposal, p-traps and removing clogs should take care of most sink smells. But if your problems are being caused by a clogged plumbing vent, you may need to call in the professionals. 

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