Stop Drain Smell and How to Prevent Drain Smells (DIY)

My cooking skills stink, but at least my drains don’t stink. Preventing drain smells is easier than stopping a stinky drain smell.

Knowing what causes that drain smell is also half the job of stopping bad drain smells.

Does that stinky drain smell make your eyes water?

Drain Smell Happens

Most homeowners at some stage face the scenario where they walk into the kitchen or bathroom and their senses are assaulted by an unknown odor. Once they’ve looked to see if something is rotting, or remove the trash to eliminate that possibility, they find that the smell is stronger at the sink, bath or shower. The first attempt to clear it is normally to run water to see if it would wash away the smell.

If the smell is in the kitchen, they may turn on the disposal to get rid of any old food that may be in there, but if that doesn’t help, it’s your drains that are smelly.

Smells coming from a drain is never a fun experience. If you have friends visiting it can be very embarrassing, but the fact is that drains often emit odors. 

We often get questions about how to get rid of the smell, and there are various causes, as well as options to freshen things up.

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If your drain smells, removing the smell is often only a few quick steps away. In this article, we’ll explain how to identify what causes the drain to smell. Plus, how to address the issue quickly and how you can prevent it from happening again. 

What Causes A Drain To Smell? – The Normal Suspects

When you notice a foul smell coming from a drain, it’s often difficult to figure out where you should start to identify the cause.

Before you can deploy the appropriate solution, you need to identify the cause of the smell. Even if you are not able to pinpoint what you’re smelling exactly, there are a number of obvious candidates that you should check out first. 

Bad drain smells are most commonly caused by: 

  • Plumbing errors
  • Water issues
  • Dry or Dirty P-Trap
  • Leaky Pipes
  • Mold or Biofilm
  • Clogs

How to Fix Drain Smells

Identifying the type of unpleasant smell is the most important and first step in knowing what to do to get rid of the odor. You should be able to identify the smell by category, i.e. sulfuric (smells like a rotten egg), moldy or musty, or like sewage.

If you are not able to describe the odor apart from saying that it’s gross, there will be clues that will help you to determine the best plan of action that will sort out your drain. 

Based on what causes the smell, here are some solutions that will help you restore the drain to its previous, unscented state.

Plumbing Errors and Old Pipe Drain Smells

When building a new home or remodeling, homeowners and plumbers sometimes make mistakes. If vents or traps are missing, it can cause a bad drain smell.

Also, old rusting drain pipes, and even extremely small leaks can cause odors in drains.

Water Issues 

Water can smell bad if there are sulfates in it. This happens often with a hot water heater when sulfate-reducing bacteria get into the system and start reacting with sulfates in the water heater. This smells like rotten eggs.

This problem can be fixed simply by turning up the heat in the water heater as this will kill the bacteria. Although water heaters are normally set to 140°F and this should kill bacteria, setting it to 160°F for a short period will eliminate the bacteria. Run the hot water for about 10 to 15 minutes, preferably in a bathtub, to flush the water heater.

However, if you do this, first ensure that your water heater has a working pressure release valve, or this may be dangerous.

Dry or Dirty P-Trap

A P-trap is what (to me) looks like a U-shaped pipe. There is one under every sink, shower drain and toilet. The shape results in it holding water at all times – unless it never gets used. Anyway, the P-trap ensures that gasses coming from the sewer line are sent to the roof vent. 

Is there no water in the P-trap due to it having evaporated? Then there is no barrier to prevent the sewer gas from escaping the drain. Simply turn on the water and run it down the drain for a short while. This should refill the P-trap and the smells will stop.

A small amount of mineral oil can be poured into drains that aren’t used regularly. This will help slow the water from evaporating out of the trap.

Debris, sediment or soil also often settles in the P-trap’s curve. This is easily cleaned by pouring ½ a cup of baking soda into the drain, followed by ½ a cup of cheap white vinegar. Cover the drain and give the mixture time to dissolve the sediment. 

If this doesn’t cure the drain smell, hydro jetting will remove the sediment and the drain smell.

Leaking Pipes

If there is even a tiny leak in a pipe behind a wall or underneath a sink, mildew and mold can build up.

Leaking pipes cause a whole host of problems. One of these is that they can allow uncomely smells to escape from the drain. When a pipe leaks, it can allow gases to escape and drift up along the plumbing. This will cause a sewage-like sulfuric smell. 

When trying to fix a leaking drain pipe, it’s crucial that you contact a professional plumber. They will ensure that each and every leak is detected and will be fixed properly. This will also prevent accidental, additional damage to the plumbing that may happen from a rookie mistake.

Contact a local plumber to get those leaky pipes fixed.

Biofilm or Mold Drain Smell

Does the unpleasant odor smell musty, or smells like mildew? There may be mold or something called biofilm in the pipes. Biofilm is a pinkish-orange colored, slimy coating that consists of bacterial waste. 

Biofilm can eventually line your whole drain and may form large blockages as more waste flows through your pipes. You can be reasonably sure that if you see slimy orange colored stains around a drain, you’re probable dealing with biofilm.

Biofilm on a kitchen drain pipe.  Source
Biofilm on a kitchen drain pipe. Source:

I will give you four DIY options to remove Biofilm:

  • To clean this bacterial substance from drains and surfaces, you’ll have to remove the drain cover. Then use a cheap kitchen scrub sponge and a cleaning solution to get rid of the biofilm from the drain. Remove what you can, rinse and scrub again until there is no more biofilm in the drain.
  • Odors caused by biofilm and bacteria can also be eliminated by plugging the sink, filling it with hot water, adding bleach and then letting it run down the drain. The bleach will kill the bacteria. DO NOT use bleach before, after or mixed with any other chemical cleaners. Bleach will react with many other chemicals to create very toxic gases.
  • Boiling water poured down the drain on its own can also kill the bacteria and help to eliminate odors. However, plastic pipes can expand when heated, which might create a leak at a joint. Also, boiling water will make rubber garbage disposal parts age very quickly.

Another option is to mix baking soda and vinegar in equal parts. When it starts fizzing, pour it down the drain, followed by hot water. Let it sit in the drain for at least an hour without adding any water. This solution is less harsh than bleach.


If you run water and it eventually starts pooling in the sink, while a bad smell comes up with it, your sewer pipe is likely blocked.

Drain clogs happen when a drain is obstructed. Blockages are usually caused by a combination of skin flakes, hair, soap scum, dirt, sand, and mineral deposits. Plus, any other object that wasn’t designed to be flushed down the drain.

As clogs trap more dirt and grime, they can often cause bad smells. If they aren’t addressed, they will cause bigger problems later on.

Drains can be unclogged by using a hand auger, also known as a drain snake. This tool will allow you to remove blockages from a drain pipe manually. Try never to use chemical drain cleaners, as these may harm your plumbing system. 

So, if snaking the pipes doesn’t help to dislodge the clog, or if the smell continues, now what? The blockage may have to be removed by a professional. One method that experts often use is hydro-jetting. This technique directs a stream of pressurized water through the pipes and this will clean any buildup inside the pipes.

Contact the Local Plumber Near Me Drain Smell Experts

Have you have tried everything you know how to do, to stop your drains from smelling badly? But you haven’t managed to get positive results? It’s time to call in a knowledgeable plumbing professional.

A local plumber will not only help you determine the cause of the drain smell, but will also take all the steps necessary to get rid of it. They have the skills and many years of experience in tackling and getting rid of bathroom and kitchen odors. 

To schedule a service use the form below:

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