Smell Sewer Gas in Your House? Try This DIY Remedy Before Calling a Plumber
How to Get Rid of Sewer Gas Smell
If you smell a noxious sewer-like odor inside your home, chances are it is sewer gas escaping from the drainage system. Not only does it smell gross, but the methane and bacteria it contains can be dangerous to your health, causing headaches or even more serious ailments. Even scarier, high concentrations of methane gas are combustible, which can cause an explosion. If you notice this distinctive, foul odor, do not ignore it.
Possible Causes for the Sewer Smell:
- sewer back-up
- leaks from rotted or cracked drain pipes
- a clogged drain
- loose-fitting pipe connections
- a stopped-up or too-short vent pipe
- toilet's wax ring is old
- a dry trap
Before you call the plumber, however, there are some simple DIY actions that may eliminate the problem quickly at little or no cost. Below, you'll find out how to get rid of the smell of sewer gas emitting from a shower drain due to a dry trap or a mild clog.
Plumbing fixtures and their connecting systems that are correctly designed and installed are normally odorless. However, even the best plumbing may sometimes allow sewer gas into your home due to a simple problem that can be easily checked…and simply solved. If the problem persists, then it’s time to call in the professional—a plumber.
DIY Shower Drain Sewer Smell Removal
- Pour 1/4 cup of baking soda into the drain.
- Follow with one cup of white vinegar.
- Let that sit for two hours with the bathroom door closed.
- Slowly pour a gallon of hot water down the drain.
- After fifteen minutes, run cold water for ten minutes to thoroughly rinse the vinegar down. This step is very important, so don't skip it.
- Pour 1/2 cup chlorine bleach into the drain and let it sit for another two hours with the bathroom door closed.
- Rinse with another gallon of hot water poured slowly.
- Let cool water run for ten minutes. By now, ample water should be standing in the “U” curve of the P-trap.
- The last step is to pour four ounces of mineral oil (plain cooking oil will work in a pinch) into the drain. The oil floats on the water in the trap and slows evaporation.
- Optional: Use a screwdriver to remove the trap if you want to replace it. You can also remove the trap to clean it out.
Warning: Never mix bleach and vinegar, or you will create toxic chlorine and chloramine gas. Step #6 is crucial to avoid this danger.
Never mix bleach and vinegar, or you will create toxic chlorine and chloramine gas.
How Does Sewer Gas Get Inside Your Home?
Every drain in your home’s sewer system should have a “p”-shaped trap that is properly vented. These drains trap water, creating a seal or barrier that will keep sewer gas out of your home. If one of these drains is rarely used, such as in a guest bathroom, the water creating the protective seal will eventually evaporate. This is a formula for trouble that can allow stinky sewer gas to seep into your home. Simply running the water might solve this problem.
P-Traps, Vents, and Drains—How They Work
Let’s consider how the plumbing for this stand-alone shower in my home operates: Water from the city water system enters through the shower head while faucets control the water pressure and supply. When water drains from the shower, it goes into the city sewer system.
My shower, indeed every plumbing fixture in my home, should have two items working together to keep sewer gas out: 1. A p-trap that holds water in a “U” shape of the pipe and forms a seal, and 2. A vent system that allows air in to equalize pressure and let sewer gases escape up the stack to the outside.
In short, the properly-vented p-trap prevents back pressure from letting sewer gas into my home. The vent is a critical component of this system because the pressure in sewer lines may fluctuate.
What Is a Dry Trap?
My research led me to believe that my stinky problem might be the easiest type to resolve: A dry trap. Since my guest shower had remained unused for a long time, the trap under the basin wasn't holding enough water to prevent sewer fumes from seeping up into the room. Often, simply running the water can resolve this issue.
Is It Okay to Pour Boiling Water Down the Drain?
While I advocate pouring hot water down the drain, what about boiling water? is it likely that boiling water in the drain might crack a pipe? I asked an engineer about this issue, and he told me that boiling water won't damage metal pipes. Even if your home's plumbing includes PVC pipes and joints, using very hot water shouldn't hurt them, but don't let the water boil.
PVC pipes don't need regular dousing with water over 175 degrees Fahrenheit (and water boils at 212 degrees Fahrenheit), or the joints might melt. If you aren't certain whether or not your plumbing system includes PVC pipes and joints (or even rubber fittings), don't let the water heat to boiling or even the about-to-boil stage. If the water is hot (less than 175 degrees F.), it should do the trick.
What If This Simple Solution Doesn't Work?
If the odor had persisted after the vinegar-baking soda-bleach-hot water-mineral oil technique I used, the sewer gas invasion might have been caused by something other than a dry p-trap.
Leaks, rotted or cracked drain pipes, clogs in the drain, or a stopped-up vent pipe are other potential stink-makers. Had I still smelled that nasty odor when I opened the bathroom door next morning, stronger measures would have been in order.
I don't have the DIY expertise to test or resolve more difficult issues, so it would have been time to call in the professional—a licensed, bonded, and insured plumber. I already have the phone numbers of two such plumbers on my speed dial (see next paragraph), but anyone searching for a trustworthy plumber should use an Internet search engine for a national or local directory of plumbers who are licensed, bonded, and insured. You don't want to take a chance on someone who may charge cheaper rates, but can't be held accountable for work, including any damages to your property.
My Experience With Sewer Gas
I didn’t know anything about p-traps or their function until a recent unpleasant incident forced me to do some hurried research. Here’s the background. There are three showers in my home. Two of them are regularly used, but the third is rarely used at all. In fact, it had not been used for months at the time this situation occurred.
When that shower was suddenly used after remaining dry for such a long period, the resulting odor emanating from the drain after the water stopped was dreadful. It smelled like…yes, a sewer! Eau de sewer is definitely not the fragrance I wanted wafting throughout my home, so getting rid of it was a top priority, requiring immediate action.
It was evening when the odor materialized, and I realized it might not be possible to get a licensed plumber to my house after regular business hours. Even if I were successful in locating a plumber who would show up before the next day, the overtime rates charged would not be healthy for my budget. Perhaps there was something I could do before then. DIY is not my forte, but I can sometimes handle an easy fix. You never know until you try.
The odor in the bathroom had to be contained, so closing off the drain holes temporarily was the first thing I did. I quickly dried the floor of the shower stall with paper towels and covered the drain tightly with good old all-purpose duct tape. I then opened the bathroom window for ventilation. Closing the door of that bathroom, I rolled up a towel and pushed it against the outside bottom of the door to prevent sewer gas from escaping that room into another part of the house.
Now that the odor was restricted, I headed for the computer and accessed Google. It took me only a few minutes to find several articles that explained how p-traps, vents (those pipes protruding from the top of the house), and a home’s plumbing drains are supposed to work, as well as what sometimes goes wrong to cause drain odors.
Since the sewer gas that invaded my home was due to a dry trap, it's up to me to keep it from happening again. I now ensure there is a water barrier in the p-trap of that little-used shower with some easy weekly maintenance. Every week, I pour a cup of white vinegar down the drain, then turn on the water and let it run for about ten minutes. This method can be used for any drain, not just the one in a shower.
If any plumbing fixture in your home gets infrequent use, try regular "preventive maintenance" by running water or flushing at least weekly to keep all the p-traps working properly. You won't be sorry for the effort to keep nasty sewer gas at bay.
When I first bought this vintage ‘60s house more than a decade ago, major plumbing problems seemed to crop up every few months. For quite some time, I had the phone number of my plumber of choice available to call quickly when emergencies arose. Finally, the big issues were resolved (and please don’t remind me how much money that cost), so visits from the plumber have been rare in recent years. (Knock on wood!) Still, I realize that letting a not-so-large problem go unrepaired often means it morphs into something much worse. All the years of plumbing problems gave me a healthy respect for those brave souls who successfully ply the trade. If a plumber is needed, at least I know a couple of good ones!
Disclaimer: I am not a plumber, building contractor, or expert in either of these fields, only a homeowner who did some research and tried the methods suggested to correct the acute issue and continue to follow it up with preventive maintenance. I hope these suggestions help you get rid of the yucky odor (and potential safety problem) of sewer gas. If they don't, you should call a professional plumber for help. Good luck!
Have you ever had to cope with sewer gas smell?
Has sewer gas ever invaded your home, and, if so, how did you get rid of it?
Questions & Answers
The smell of sewer gas does not come from inside my house; it is coming from the roof ventilation. Do I have to treat the smell the same way?
The roof vent probably has a blockage--debris the wind blew in, a bird's nest, etc. A handy DIY-er with a steady ladder may be able to unstop it. That should stop sewer gas from backing up into the house. However, there may be another problem with your roof vent that may require a plumber.Helpful 29
If the sewer flows into a septic tank, can I use vinegar or bleach to relieve sewer gas?
Pouring vinegar in your toilets won't harm the septic tank, nor will it kill the beneficial bacteria as chemicals would.Helpful 22
I tried the DIY tactic to eliminate the sewer smell, and it came back. Should I repeat this method?
It make take two or three times for the trap to stay wet and eradicate the sewer gas smell. Don't forget to add the four ounces of mineral oil, which will help keep the trap wet.Helpful 5
My toilets have overflowed more than once, and now my house smells like poop. What can I do?
This is not a DIY issue except for floor cleanup and disinfecting. You need a plumber to determine what is causing repeated overflows and repair it. There may be a blockage in your system.Helpful 12
If a dry P-trap caused the odor, why did it only become an issue after running the shower after adding water to the trap? It seems like it should have been noticeable before use, rather than after.
Was your shower not in use for some time, as in a guest bathroom only used occasionally? It may require several of the DIY treatments I mention in my article to keep the trap properly wet. If the smell continues after using the tips for a dry trap (including 4 ounces of mineral oil to hold the moisture in the trap), it may be caused by something else that should be diagnosed by a plumber.Helpful 9
© 2011 Jaye Denman