Why Does My Drain Smell Like Rotten Eggs? (And When It’s a Sewer Gas Emergency)

The scent of rotten eggs anywhere in your home is never a good thing. Apart from the bad smell, it is a warning sign that something is very wrong. While the smell of rotten eggs in your home is a red flag for a gas leak, a rotten egg or sulfur stench coming from your drains specifically could actually be a sewer gas smell. Sewer gas is composed of many different harmful toxins, like ammonia, methane, and carbon dioxide, among others. While you should act on it immediately, it is not necessarily a sewer gas emergency if you are smelling something rotten in your drains. Let’s go over the many explanations and solutions for the rotten egg smell coming from your drain, as well as when you can assume it’s an emergency and need to call a plumber.

Sewer Gas Smell From Clogged Drains

One basic explanation for a rotten egg smell in drains is that there is a clog. When there is a clog in your sink or shower, it creates a blockage where bacteria builds up and creates the odor. You very likely have a clog if you’re noticing the smell coming from one drain specifically and it also drains slower than usual.

A possible solution to this is to create a baking soda and vinegar mixture to pour down the drain which can dissolve the clog as well as clean out your drain entirely. Pour a half cup of baking soda followed by a cup of white vinegar into the drain. Then pour a pot of hot water down the drain after you’ve let the mixture sit for a little while, washing away the leftover debris.

Buildup in Garbage Disposal

If the smell is coming from your kitchen sink drain, it is possible that a dirty garbage disposal is the culprit rather than a sewer gas emergency. This is a place where food can collect and grow bacteria over time, leading to kitchen sink drain smells.

To clean your garbage disposal, fill the sink with ice cubes, run cold water, and turn on the disposal. The ice cubes will knock off residue build up on the blades. You can then add orange peels or lemon wedges into the sink in order to freshen the smell.

No Water in P-Trap

A dry p-trap is a common culprit of nasty sink drain smells. A p-trap is a curved section of the pipe in your drains that holds a bit of water in order to block sewer gases coming back up and into your home. When this dries up, perhaps from the drain not being used in some time, it can be the source of rotten egg smell in drains.

Simply running the water for a couple of minutes should be enough to refill the p-trap and remove the sewer odor. It is a good idea to pour a gallon of water down any frequently unused drain every month or so in order to avoid a dried out p-trap.

Biofilm Building Up in Drains

A buildup of biofilm can happen if it has been a while since you’ve cleaned your drains, and can certainly be the source of rotten stenches. When bacteria mixes with soap scum, grease, dirt, hair, or other materials that are lingering in the drain, it creates a slime-like matter called biofilm, and could be the reason your kitchen or bathroom smells like sewage.

Again, a good solution for this is a natural drain cleaning method like the baking soda and vinegar mixtures. This mixture is not only for dissolving clogs, but also cleaning the sides of your drain from bacteria such as this. It is a good idea to implement a regular drain maintenance routine to keep things like soap and grease buildup out of your drains and prevent biofilm. Using drain screens to catch debris is another important tool in maintaining drain health.

Hidden Pipe Leaks

If there is a hidden plumbing leak, such as a water pipe leaking somewhere in your floors or walls, this can cause a rotten smell to appear in your home, especially if there is a leak in the drain waste line. Cracks in pipes can lead to the sewer gas coming through your home.

If you notice other signs of a hidden leak, such as unusually high water bills, low water pressure, water damage or random wet patches, and mold growth, call a leak detection specialist right away to locate the hidden water leak so that it can be repaired.

Blocked Plumbing Vents

A blocked plumbing vent pipe can also be the reason sewer gases are traveling back through your drains and leading to a strong sewer odor. The plumbing vent pipe is designed to filter the sewer gases through the roof of your home where they can safely stay out of the house, but when debris or design failures cause the pipe to become blocked, it can cause issues.

This is a case where a professional plumber would have to get involved in order to inspect the pipe fully and find a repair solution.

Water Heater Anode Rod

Your water heater can be the source of the rotten egg smell in drains, particularly if you notice the smell when running hot water in all your appliances. This comes from hydrogen sulfide gas, which has a similar smell to sulfur. The anode rod in your water heater is designed to attract corrosion so that the water doesn’t rust, and this can create this bacteria reaction.

Flushing the tank is a great way to rid this issue, as well as replacing the anode rod if it is overly corroded. These two regular maintenance tasks are important to keep up either on your own or with the help of a water heater professional.

Do I Have a Sewer Gas Emergency?

But when does this situation become an emergency? Sewer gases can be highly dangerous in large amounts, so if you notice the issue and none of the above solutions work, you should call a plumber right away.

Also, if you are noticing the problem occurring along in several of your drains throughout the house, along with multiple slow or gurgling drains, this points to a large blockage in the sewer main line, the pipe that carries all your household’s waste water to the municipal sewer system. This can quickly turn into an emergency situation, so sewer experts should be contacted immediately.

Lastly, if you’ve noticed physical symptoms like dizziness, nausea, and headaches, you should evacuate the area right away and contact emergency services.

Who Should I Contact for a Sewer Gas Emergency?

John Owens Services has been in the drain and sewer business for forty years. Since 1986, we have served the Sonoma and Marin County areas with emergency solutions for sewer backups that leave them with clear, safely flowing drains. We offer emergency plumbing services like sewer cleaning, repair, and replacement. We also provide basic drain maintenance services like inspections, hydrojetting, and rooter services to remove tree roots from sewer pipes, which can be the cause of large main line blockages. Contact us today or visit our drain cleaning quote tool to learn more about our services.

Key Takeaways

• Check for clogged drains; try the baking soda and vinegar method if a smelly drain is also moving slowly
• For kitchen sink drain smells, trying cleaning the garbage disposal
• Make sure there is always water in all p-traps by running the water for a couple minutes in drains that are not frequently used
• Keep an eye out for signs of water leaks, such as mold spots, wat patches, and water damage in your home
• Perform regular drain maintenance like cleanings and using drain screens to prevent the growth of biofilm
• Keep up with waiter heater maintenance like tank draining and changing corroded anode rods to prevent hydrogen sulfide gas from getting into hot water
• Call a plumber for any other issues, particularly if a sewer gas smell is persisting or you have multiple drains emitting the sewer odor