Sewer Gas Smell in Bathroom: How to Identify & Get Rid of Odors

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After you've flushed your toilet, you probably don't want to see or smell the contents ever again. Unfortunately, that's not always how it works. You may notice a sewer gas smell in your bathroom at some point in time, and that foul odor is exactly what you think it is. There are several potential culprits that could be the source of the odor.


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Sewer Gas Smells and Safety

A sewer gas smell is more than just unpleasant — it's also potentially dangerous. Exposure to sewer gases can cause nausea, dizziness, and hydrogen sulfide poisoning, which can be fatal. Airborne pathogens can also find themselves carried into your home via the gas. When allowed to accumulate, sewer gas can also explode.


To avoid these problems, you'll want to address sewer gas smells as soon as possible. If the odor is already overpowering, wear a painter's mask while you fix your gas problem or call in a plumber for help. When you start looking for the source of the smell, begin with the most common sources of the problem, ruling out the simple stuff before diving into more complicated issues.


Check for Dry P-Traps

Your sink drains, shower drains, and toilet all contain p-traps. Consisting of a U-shaped pipe, p-traps hold a bit of water at all times to keep sewer gases from making their way into the room. These traps will dry out if the drain isn't used frequently enough. If this is the case, simply run a little water down the drain to fill the trap again and the sewer smell should go away.


Check for a Clogged Drain

If your bathroom smells bad and the drains are moving slowly, you likely have a clog somewhere in your pipes. To remove it, pour 5 quarts of hot water down the drain. The water should be hot but not boiling as this can damage your pipes. You don't want the water any hotter than 150 degrees Fahrenheit.


After pouring the water down the drain, follow it with 1 cup of white vinegar and 1/2 cup of baking soda. Wait 2 hours for the mixture to do its work and then follow it up with another 5 quarts of hot water. If this doesn't free things up, snake the drain or call a plumber to do so. Don't pour bleach or chemical drain treatment into your pipes as these can cause damage and may do more harm than good.


Clear Your Vent

The vent pipe is a crucial component of your plumbing system. If it gets blocked or clogged, you can experience sewer gas smells in your home and may hear your pipes gurgle. Your vent is on your roof, and you need to make sure there aren't any tree branches, bird nests, or other debris blocking it. If there are, removing the blockage may solve your odor problem.


If you don't feel comfortable getting on the roof, ask a friend or family member for help. Don't risk getting hurt. Again, calling a plumber is an option if you're more comfortable with that choice.

Examine the Septic Tank

Septic tanks generally need emptying once every 3 to 5 years. If you're overdue or if your family uses more water than average, your smell may indicate that the septic tank is full. Other indicators of a full tank include slow drains, puddles in the lawn, and a stinky yard. If your septic system has an issue, tending to it may eliminate bad smells in the house and yard.


Wiggle the Toilet

Before being bolted to the floor, toilets are set down on a wax ring. This ring creates a seal that prevents sewer gasses from creeping up through your plumbing, Over time these wax rings dry out and eventually fail, which makes the area around the toilet smell. Sometimes when they do the toilet itself will wiggle back and forth a bit when gently rocked.

Replacing a wax ring is a pretty easy job, but you do have to remove the toilet to do it. You can have a plumber do the work if you want, but doing it yourself is manageable. You'll just need to disconnect the water, drain the toilet, undo the nuts on either side and lift the toilet up off the bolts.

When looking for instructions on fixing a smelly toilet, don't take the often posited advice that you should caulk around the base of the toilet and/or the bolts. This is popular but bad advice. Caulk is no substitute for a wax ring and will block the smell only temporarily if at all. Caulking also makes removing the toilet in the future more difficult.

Call in a Pro

If none of the simple fixes work, you may have a more sinister problem on your hands. It's possible that tree roots have grown into your plumbing or that you have a backup further in your system than you can reach on your own. Broken or collapsed sewer pipes may also be to blame. You may have trouble even identifying these issues on your own, let alone fixing them.