When it comes to smelly sinks, a dishwasher running can often be the culprit.
Whether it’s an issue with the drain pipes or something more complicated like a blocked air gap, there are a number of possible causes for why your sink is emitting a foul odor when the dishwasher is running.
In this blog, we explore the most common causes of smelly sinks and provide practical tips and solutions to help you identify and address the source of the bad smell.
Identify the Source of a Bad Smell in Your Sink
Here are the 15 possible reasons for a sink smelling like rotten eggs when the dishwasher runs:
Damaged or Leaking Drain Pipe:
If you notice a bad smell coming from your sink when your dishwasher runs, it could be due to a damaged or leaking drain pipe under the sink.
Harmful sewage gases can escape through these pipes, and you need to fix the issue as soon as possible.
Improperly Sized or Installed P-Trap:
You might have an improperly sized or installed P-trap that is designed to prevent sewer gases from entering your home. This can cause unpleasant smells to escape into your sink.
Clogged or Blocked Dishwasher Air Gap:
The dishwasher air gap is a small device located next to your sink that prevents dirty water from flowing back into the dishwasher.
When it gets clogged or blocked, it can cause odors to build up in your sink.
Broken or Malfunctioning Sewage Ejector Pump:
If there’s a bad smell in your sink when the dishwasher runs, it could be due to a broken sewage ejector pump.
This pump is responsible for pumping waste water from below-grade plumbing fixtures to the sewer line.
Buildup of Grease or Fat in the Pipes:
A buildup of grease or fat in the pipes can cause a foul smell in your sink when the dishwasher runs.
This is because the grease or fat can interact with other substances and create unpleasant odors.
Faulty Dishwasher Pump:
A faulty dishwasher pump can also cause a bad smell in your sink when the dishwasher runs.
If the pump is not working properly, it can cause food particles to build up and produce unpleasant odors.
Corroded or Damaged Dishwasher Heating Element:
When the dishwasher operates, you may be able to smell something bad coming from your sink, if the heating element of the appliance is corroded or not functioning properly.
This happens because the heating element can react with other substances and generate unpleasant odors.
Dirty or Clogged Dishwasher Filter:
One potential source of a bad smell in your sink when the dishwasher is running could be a dirty or clogged dishwasher filter.
Unchecked, a clogged dishwasher filter can cause water to become stagnant, leading to bacteria and food particles festering in the filter and causing an unpleasant smell.
Malfunctioning Water Softener:
If your sink smells bad when the dishwasher runs, it could be coming from a malfunctioning water softener.
This could be caused by a clogged filter, a defective brine tank, or a faulty control valve.
Cracked or Broken Drain Pan:
If you notice a bad smell coming from your sink when the dishwasher runs, it is likely due to a cracked or broken drain pan underneath it.
The cracks or breaks may allow food residue and soap residue to escape, resulting in an unpleasant smell.
Check the pan carefully, and if necessary, replace it to keep the smell away.
Malfunctioning Water Heater:
If the water heater is malfunctioning, it can cause a bad smell in your sink when the dishwasher runs.
This is because hot water can interact with other substances and create odors.
Buildup of Soap Scum or Residue in the Dishwasher or Sink:
A buildup of soap scum or residue in the dishwasher or sink can cause a bad smell when the dishwasher runs.
This is because the soap scum or residue can interact with other substances and create unpleasant odors.
Improperly Vented Plumbing System:
If your plumbing system is not properly vented, it can cause a bad smell in your sink when the dishwasher runs.
This is because the vent is responsible for removing harmful gases from the plumbing system.
Improperly Installed or Damaged Vent Stack:
If the vent stack is improperly installed or damaged, it can cause a bad smell in your sink when the dishwasher runs.
This is because the vent stack is responsible for removing harmful gases from the plumbing system.
Buildup of Hydrogen Sulfide:
A buildup of hydrogen sulfide in the pipes can cause a bad smell in your sink when the dishwasher runs.
This is because hydrogen sulfide can interact with other substances and create unpleasant odors.
Possible solutions for fixing a sink that smells like rotten eggs when dishwasher runs
1. Clean and unclog the drain pipes
- Use a drain snake or hydro jet to remove any blockages in the drain pipes.
- Use a mixture of baking soda and vinegar or a commercial drain cleaner to dissolve any grease, soap scum, or food debris.
- Consider hiring a professional plumber if the blockage is severe or if the pipes are damaged.
2. Repair or replace inadequate venting
- Ensure that the vent stack is properly installed and free from damage.
- Install a proper venting system to ensure proper airflow and prevent sewer gas or methane buildup in the pipes.
- Consult with a licensed plumber to determine the best venting solution for your specific plumbing system.
3. Clean and sanitize the dishwasher or sink
- Use a mixture of warm water and dish soap to clean the dishwasher or sink thoroughly.
- Run the dishwasher through a hot water cycle with vinegar or a commercial dishwasher cleaner.
- Use a mixture of baking soda and water to clean the garbage disposal and remove any food debris or grease buildup.
4. Replace old or deteriorating plumbing components
- Inspect the plumbing system for any signs of damage or deterioration.
- Replace any damaged or corroded pipes, joints, or fittings with new ones.
- Hire a licensed plumber to perform the repairs if you are unsure of how to replace the plumbing components.
5. Reconfigure or reinstall the plumbing
- Consider reconfiguring or reinstalling the plumbing system to improve drainage and ventilation.
- Consult with a licensed plumber to determine the best solution for your specific plumbing system.
- Ensure that the plumbing system meets local building codes and regulations.
6. Use a water softener to reduce hard water buildup
- Install a water softener to reduce mineral buildup in the pipes.
- Use a water softener cleaner to remove any buildup in the water softener system.
- Hire a licensed plumber to install the water softener if you are unsure of how to do it yourself.
7. Ensure adequate water supply
- Ensure that the dishwasher and sink are receiving an adequate water supply.
- Check for any leaks or damage in the water supply line.
- Hire a licensed plumber to repair or replace any damaged water supply lines.
8. Repair or replace faulty dishwasher components
- Inspect the dishwasher for any signs of damage or malfunction.
- Replace any faulty components, such as the dishwasher pump or heating element.
- Hire a licensed appliance repair technician if you are unsure of how to repair or replace the dishwasher components.
9. Clean and unclog the garbage disposal and dishwasher filter
- Remove any food debris or grease buildup from the garbage disposal and dishwasher filter.
- Use a mixture of warm water and dish soap to clean the garbage disposal and dishwasher filter.
- Run the dishwasher through a hot water cycle with vinegar or a commercial dishwasher cleaner.
10. Use a drain clHeaner or enzyme treatment
- Use a commercial drain cleaner or enzyme treatment to remove any grease or food debris buildup in the pipes.
- Follow the instructions on the product label carefully.
- Consider using an eco-friendly or natural drain cleaner to avoid damaging the pipes or harming the environment.
11. Repair or replace a malfunctioning garbage disposal unit
- Inspect the garbage disposal unit for any signs of damage or malfunction.
- Replace any damaged or faulty components, such as the motor or blades.
- Hire a licensed appliance repair technician if you are unsure of how to repair or replace the garbage disposal unit.
12. Repair or replace a broken drain trap
- Inspect the drain trap for any signs of damage or deterioration.
- Replace the broken drain trap with a new one.
- Hire a licensed plumber to perform the replacement if you are unsure of how to replace the drain trap.
13. Check the dishwasher detergent and rinse aid
- Use the correct amount and type of dishwasher detergent and rinse aid.
- Avoid using too much detergent or using non-dishwasher safe items.
- Use a high-quality dishwasher detergent and rinse aid to prevent buildup in the dishwasher.
14. Clean the dishwasher spray arms and nozzles
- Remove the dishwasher spray arms and nozzles.
- Clean them thoroughly with warm water and dish soap.
- Reattach the spray arms and nozzles to the dishwasher.
Preventing future smelly sink situations:
1. Run hot water down the drain
Running hot water down the sink drain for at least 30 seconds after each use is an effective way to help flush out any food particles and prevent them from accumulating and causing bad odors.
The hot water helps to break down any leftover food and grease, which can prevent them from building up in the pipes and creating blockages.
2. Use a garbage disposal
If your sink has a garbage disposal, use it to help grind up food particles and prevent them from sticking to the inside of the pipes and causing odors.
Make sure to run the garbage disposal regularly and use cold water while it is running to help solidify any grease or oil, making it easier to chop up and flush down the drain.
3. Avoid pouring grease and oil down the drain
Grease and oil can solidify in the pipes and cause clogs that can lead to bad odors. Instead, pour them into a separate container and dispose of them in the trash.
Grease and oil can also damage your garbage disposal and cause it to malfunction.
4. Use a sink strainer
Using a sink strainer to catch food particles is an effective way to prevent them from going down the drain and causing bad odors.
Empty the strainer regularly and wash it with warm, soapy water. This helps to prevent food particles from accumulating in the drain and pipes, which can lead to blockages and odors.
5. Clean the sink regularly
Cleaning the sink and drain regularly with a mild cleaner helps prevent bacteria growth and odors.
Use a cleaner that is safe for your sink’s material and rinse it thoroughly after cleaning.
This helps to prevent buildup of bacteria and food particles, which can cause bad odors.
6. Maintain proper ventilation
Make sure your kitchen and bathroom are properly ventilated to prevent moisture buildup and mold growth, which can lead to bad odors.
Use exhaust fans or open windows to improve airflow. Proper ventilation also helps to prevent the accumulation of cooking odors and moisture, which can cause bad odors in the sink and drain.
Can I use regular sink cleaners to get rid of the bad smell?
Using regular sink cleaners may not be enough to completely eliminate the bad smell, as the source of the odor may be inside the dishwasher.
Instead, you can try using specialized dishwasher cleaners or running a cycle with vinegar or baking soda.
What if the bad smell persists even after cleaning the dishwasher?
If the bad smell persists, it may be due to a clog in the drain hose or a problem with the garbage disposal.
In this case, it is recommended to call a professional plumber to diagnose and fix the issue.
Why Does Only One Sink Smell Like Rotten Eggs?
Sulfur is the primary culprit in causing sinks to smell like rotten eggs.
The gas is emitted when water and metals like copper react, and it’s also what gives hot springs and mineral baths their distinctive smell.
There are a number of possible causes of smelly sinks when the dishwasher runs, ranging from a damaged or leaking drain pipe to a buildup of grease or soap scum in the pipes.
It is important to take the necessary steps to identify and address the source of the bad smell in order to prevent any further damage or odors.
With proper maintenance and the right solutions, you can ensure that your sink is free of bad smells and running smoothly.