Informational Guide

Sink Smells Bad: Sewer & Rotten Eggs (How To Get Rid Of)

If you are looking for ways to identify, treat, and prevent sewer & rotten egg smells from your sink, read on to find our handy tips.

by Matt Moran

Coming home to find that your sink smells bad is always an unpleasant surprise. This rotten egg smell is often an indicator of deeper plumbing issues.

If you are looking for ways to identify, treat, and prevent sewer smells, read on to find our handy tips.

Sulfur Bacteria

In groundwater, wells, and water distribution systems, hydrogen sulfide often occurs when bacteria comes into contact with sulfide compounds. This causes a chemical reaction to occur and creates hydrogen sulfide gas. This gas can enter through your pipes and plumbing system to create unpleasant kitchen sink smells. It is possible to treat your water and distribution system to prevent this from happening in the future.

Sewage or Pollution

Sewer waste can also create this familiar rotten egg smell. However, as it is dealt with separately from your groundwater, it is rare for the two to mix. Sewer waste can get into your groundwater system and cause you to smell the offensive odor in rare instances. If your sewer smell is coming from the sink, it may mean that you have a broken or dried-out p-trap.

Ground Waters

Groundwater is a valuable resource for your home that, while useful, can be prone to bacterial growth. Hydrogen Sulfide is typically formed when the chemical matter in the water decays or when the bacteria comes into contact with minerals and rocks containing sulfur. A chemical reaction occurs and produces these noxious fumes, which can push through your plumbing system and into your home. We recommend treating the groundwaters on the advice of a professional plumber.

Water Heaters

Water heaters provide warm water to our homes, vital to everyday cleaning and self-care tasks. However, they are not exempt from causing nasty smells. Warm water is an ideal environment for helping bacteria grow. What can happen in water heaters is that the tank's electrons can react with sulfate to become hydrogen sulfide. It is possible to treat this issue and prevent it in the future.

Where Is The Bad Smell Coming From?

Contaminated Water

If your water is contaminated, it could be coming from your water heater. The magnesium in a rod could be reacting with the bacteria to create the fumes.

Contaminated Sink Drain

Grease, fat, food, hair, and skin oil can all build up over time in your sink drains and create some unpleasant smells as bacteria develop and the food rots.

Clogged or Blocked Pipes and trap

If your pipes and p-trap are clogged, this can cause a build-up of food and water. The longer this blockage sits, the more bacteria can build up in the stagnant water and create unpleasant smells.

Clogged or Cracked Vents

If you have an iron vent pipe, it may be cracked or clogged by rust that decays in the water. Alternatively, it could be blocked by tennis balls, leaves, and other debris. While you can remove clogs with an auger, cracked pipes are more severe and will require a professional.

Biological slime

While kitchens have to deal with food and grease-related clogs, bathrooms have another type to contend with. Caked-on soap can mingle with shampoo, skin oils, and hair to form biological slime that sticks to your pipes and creates unpleasant bathroom sink smells.

How Do You Get Rid Of A Smelly Sink?

  • Use Boiling Water
    Boil a kettle and pour the hot water down the sink. Wait five minutes before pouring an equal amount of cold water into your pipes.
  • Use A White Vinegar
    If you want an alternative to harsh industrial chemicals, try using white vinegar. Pour one cup of white vinegar down the sink, let it stand for 30 minutes, and then run hot water through your system. As vinegar is a strong acid, we do not recommend doing this regularly.
  • Use Caustic soda
    Caustic soda, or sodium hydroxide, is an excellent degreasing product that can cut through nasty stuck-on debris in your pipes. Dissolve 100g in a liter of water and pour it down the drain. Wait 30 minutes before running cold water through your system.
  • Use a Plunger
    Place the plunger over the drain to form a seal. Push up and down on the handle as much as possible for at least a minute. Once you are ready, pour hot water down the sink drain.
  • Check the U Bend
    Place an empty bucket underneath the u-bend and remove it with a wrench. Using a wire brush and clean soapy water, clean the pipe until it is spotless before replacing it. Flush the system with warm water to check if there are any more blockages.

How To Prevent Your Sink From Smelling

Preventing sink smells from occurring is key to prolonging your system's life. We recommend:

  • Performing the above tasks regularly.
  • Being mindful of what you put in the sink and avoiding some foods.
  • Never pour oil or grease into your sink.
  • Clean your garbage disposal regularly.
washing area


What are the long-term risks of prolonged Hydrogen Sulfide exposure?

Long term risks include poisoning, asphyxiation, fire, and explosions.

How do you freshen a smelly drain?

By cleaning your system as above, you can help prevent any nasty smells. If you have a garbage disposal, you can use citrus wedges to create a pleasant aroma.

What happens if you breathe in sewer gas?

Depending on your exposure level, you could experience:

  • Eye irritation
  • Coughing or short breath
  • Inflammation
  • Headaches
  • Fatigue

And more.


If it smells like something died under your sink, you need to deal with it quickly. Try the methods above and, if the smell remains, contact a local plumbing professional for help.

Matt is a freelance writer, English graduate, & keen traveler from the UK. As a specialist plumbing expert, he enjoys writing about everything there has to do with at-home plumbing products & related problems. When he isn’t writing, he’s usually drinking coffee or planning his next adventure. In his spare time, he also runs his own blog all about digital nomad life.