Highlights
The most dangerous cause of a rotten egg smell is a gas leak.
When you smell sulfur in your home, go outside and contact a local gas professional.
Once a pro rules out a gas leak, troubleshoot other causes–like drain pipe issues.
Other causes of the smell include sulfuric well water and broken drain pipes.
Get quotes from up to 3
pros
!
Enter a zip below and get matched to top-rated pros near you.
Your home is your sanctuary, and nothing ruins a sacred space more than the smell of rotten eggs. Sulfur is a uniquely atrocious odor, and one whiff will send you looking through your house for the cause. Follow this guide to learn all about the six common causes of this nose-pinching odor and tips to eliminate it once and for all.
1. Gas Leak
A gas leak is the most dangerous cause of that rotten egg smell, and it is by design. Natural gasses are typically odorless, which presents an extreme danger in the case of a leak. To solve this problem, gas companies started adding a chemical called mercaptan to give their gas supply that distinctive sulfuric odor. Without this additive, you’d have no way of knowing when you were experiencing a life-threatening gas leak.
What to Do
You need to rule out a gas leak as the cause of the smell immediately. Do not turn on or handle any electrical equipment in your home. Leave the house and call the authorities or contact a local gas leak repair specialist. Gas leaks are serious, so bring in a pro before considering any of the other options on this list. Better safe than sorry, right?
Repairing a gas leak costs anywhere from $120 to $250 on average, though you may have to spend an additional $270 to $760 to repair drywall if your pro needs to cut through it to get to the gas line. Still, this is a small price to pay for your family’s safety.
2. Dry Drain Pipes
Photo: zhihao / Moment / Getty Images
Once you’ve ruled out a gas leak, it’s time to roll up your sleeves and have a look around your home for the stinky culprit. Dried-out drain pipes are another common cause of that rotten egg smell in the home. Dry drain pipes often happen with guest bathrooms, or bathrooms in vacation homes, that remain relatively unused.
Sinks and tubs connect to something called a plumbing trap, or P-trap. As the name suggests, a P-trap is a P-shaped pipe that traps sewer gas and prevents it from heading into your home by creating a layer of water on the bottom of the curve. If the water evaporates, the sewer gas happily wafts into your home, creating a sulfur odor in the process.
What to Do
Often, the fix for a leaky P-trap is simple. Run cool water in any sinks and tubs in the impacted bathroom for 10 minutes. This method allows the P-traps to build up the necessary amount of water to block that nasty sewer gas. Alternatively, you can try pouring a cup of vinegar or bleach down the drain—you’ll get the added bonus of a shinier, cleaner sink while you’re at it.
If these tips don’t work, contact a local plumber for some advanced troubleshooting. They may recommend the installation of a dedicated sewer gas trap or the replacement of your p-trap.
3. Gassy Drywall
Most people assume that drywall is completely solid and poses no risk of creating any odors whatsoever, let alone the smell of rotten eggs. Unfortunately, that is not true, especially for homeowners who built houses or renovated their houses between the years 2001 and 2009. During those years, many contractors imported drywall from China that contained excessive amounts of sulfur. The result? Drywall off-gassing a sulfuric odor throughout your home.
What to Do
Though contractors no longer import the offending drywall, many homes still include drywall sheets from the era. Authorities recommend homeowners check the copper coils in their refrigerators or air conditioning units, looking for tell-tale black ash on the copper coils that builds up when drywall emits consistent levels of sulfur.
Once successfully diagnosed, the only solution is to contact a local drywall contractor and replace all of the infected drywall. Check your homeowner’s policy or homeowner’s insurance plan to suss out any potential coverage to offset the costs. Otherwise, replacing drywall costs an average of $60 to $90 per panel.
4. Well-Water Issues
Photo: Kentaroo Tryman / Maskot / Getty Images
According to the Environmental Protection Agency (EPA), over 13 million American households rely on well water instead of treated water from a local municipal agency. Like sewage pipes, however, wells are susceptible to the smell of sulfur. In this case, the water itself develops the odor, thanks to a buildup of hydrogen sulfide caused by decaying vegetation in the ground. It’s not a dangerous occurrence, but it doesn’t create the most appealing drinking water.
What to Do
The nose knows. Diagnose the issue by shutting off the water in your home for six hours, filling your sink up with several inches of cold water, and taking a strong whiff. If the smell of rotten eggs hits you in the face, you’ve unmasked the culprit.
For an even stronger confirmation, send a sample of your water to your local extension office by requesting a water testing kit. What’s the fix? Plumbers recommend installing a carbon filter on your drinking faucets and installing a reverse osmosis system or water softener system in your home.
5. Sewer-Line Issues
Beyond a dried-out P-trap, many other sewage-related malfunctions result in the appearance of nasty odors. For instance, broken drain pipes allow sewer gasses to seep out and run amok throughout your home and exterior property. Clogged drain vents also lead to various plumbing odors, and so on. Your plumbing system is finely tuned and fragile, and any number of issues lead to unwanted smells.
What to Do
Troubleshoot on your own by running water throughout your home and watching for slowly running drains. Also, listen for a distinct gurgling sound when sinks drain or when toilets flush. Both of these symptoms suggest a clogged drain vent.
It is possible to clean and unclog a plumbing vent on your own, but amateurs should call in a plumber. Competent plumbers can also diagnose broken drain pipes even when a clogged sewer line lurks outside your home. Plumbing repairs cost around $325 on average, but can range from $75 to $4,000.
6. Actual Rotten Eggs
Sometimes if it looks like a rotten egg and smells like a rotten egg, it’s a rotten egg. Expired eggs and other spoiled food items create all manner of foul odors throughout your home. Though eggs last a while before spoiling, the same is not true of other ingredients like chicken, avocado, green beans, bananas, mushrooms, and others.
Additionally, cooked ingredients can spoil and emit disgusting smells, so keep an eye on your cold-pressed juices and whatever leftovers lying in the refrigerator.
What to Do
Clear out the offending ingredients, throw them in the trash, and immediately throw out the trash. After that, clean the refrigerator with a multi-purpose cleaner and install a mild air freshener in your kitchen or the fridge. Also, set your refrigerator’s thermostat to 40 degrees Fahrenheit or below to stave off early spoiling.
When to Consult a Pro
If you’ve played detective, exhausted your options, and everything turned up inconclusive, you shouldn’t give up. An unresolved rotten egg smell in your house could still pose a threat to your home—not to mention, the sheer smell of it can impact your everyday life.
If you’ve already had a gas company near you inspect your home to rule out a gas leak, it’s time to pass the baton over to a different professional—a plumber. Contact your local plumber to investigate the issue and get to the bottom of that rotten egg smell so that you can take a deep, worry-free breath.
A licensed plumber has the tools and expertise needed to get to the bottom of any sewage or drainage problems. They’ll use diagnostics to uncover hidden leaks or clogs, and fix them so that your home is safe.
