Slight Sewer Gas smell coming from bathroom - Problem solved -maybe!

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Brewman
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Slight Sewer Gas smell coming from bathroom - Problem solved -maybe!

Post by Brewman »

I have an upstairs bathroom where I am starting to get a sewer gas odor? :? It seems to be intermittent but still noticeable. Both sinks and tub/shower have water in the traps from regular daily use. Smell seems to be coming from around the toilet (go figure) there are no obvious leaks that can be seen. Once the weather warms I'll get on the roof and check the vent stack for a possible birds nest etc. Any other thoughts that could be causing it? Could the wax ring not be sealed well - well enough to not have a water leak but not well enough to contain the gas? I want to check what I can before I call a plumber. Oh, and yes the smell is there before the bathroom toilet is used! :D

I appreciate any insight

Edit - I was able to get on the roof Saturday to make sure the vent stacks were clear - shined a flash light down and all looked good. Next I pulled the hatch off the chase that is on the wall by the toilet that gives access to the Shower/tub plumbing - no smell and all looked dry. Lastly I checked the two bolts that hold the toilet in place and they had nylon bolts that you could tighten by hand and both bolts were slightly loose? So I carefully tightened them by hand being able to probably get a full turn and half on each...careful not to over tighten! No smell since I did that! :D
Could it have been that simple :oops: Planning to give it a week or two to be sure but I'm wondering if I should still have it checked?
Last edited by Brewman on Mon Mar 15, 2021 8:27 am, edited 1 time in total.
realclemsongrad
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Re: Slight Sewer Gas smell coming from bathroom

Post by realclemsongrad »

I had one of this. It ended up being the shower clogged with hair. Thanks
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lthenderson
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Re: Slight Sewer Gas smell coming from bathroom

Post by lthenderson »

Brewman wrote: Fri Mar 05, 2021 1:11 pm Could the wax ring not be sealed well - well enough to not have a water leak but not well enough to contain the gas?
That was my first thought. It doesn't take much of a crack or leak in a wax ring to allow gas but effectively stop 99% of the water. I've pulled up many a toilet that was sitting on rotten wood from years of leaking that the homeowner swore never leaked.
Teague
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Re: Slight Sewer Gas smell coming from bathroom

Post by Teague »

Depending on the type of flooring, and the toilet installation, could be a leaky wax ring with some foul water hidden under the vinyl or other flooring material.

For this reason, when installing a toilet I leave a 1 inch gap at the back side when caulking around the base. That way a water leak is more likely to become apparent as it leaks out on top of the flooring. If the base is sealed all the way around water can accumulate occultly and cause the issue you describe, and other problems.
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hicabob
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Re: Slight Sewer Gas smell coming from bathroom

Post by hicabob »

lthenderson wrote: Fri Mar 05, 2021 1:29 pm
Brewman wrote: Fri Mar 05, 2021 1:11 pm Could the wax ring not be sealed well - well enough to not have a water leak but not well enough to contain the gas?
That was my first thought. It doesn't take much of a crack or leak in a wax ring to allow gas but effectively stop 99% of the water. I've pulled up many a toilet that was sitting on rotten wood from years of leaking that the homeowner swore never leaked.
I bought a house a long time ago with 3 toilets in which the previous owner was purportedly an easy 350 lbs. Every toilet needed the floor replacing from the wax ring leaking. My theory was that heavy people are tougher on wax rings.
squirm
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Re: Slight Sewer Gas smell coming from bathroom

Post by squirm »

Take out the toilet and put in a big wax ring.
JBTX
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Re: Slight Sewer Gas smell coming from bathroom

Post by JBTX »

realclemsongrad wrote: Fri Mar 05, 2021 1:19 pm I had one of this. It ended up being the shower clogged with hair. Thanks
I had similar issue, smelly shower bottom. I cleaned it out with toilet brush, it would smell better for a while but quickly came back. I saw a YouTube video that said it may be seeping or soaking into something else. I'd let the shower bottom soak in a hospital disentfrctant overnight and that diminished the issue a week or two. Finally I noticed when I switched from "clean shower" daily shower cleaner, which I can't find anymore, to a highly diluted mixture of vinegar alcohol and dawn soap there have been no more issues. Also occasionally running vinegar in the rinse cycle where fabric softener goes has gotten rid of the occasional funky smell there.

Downside is vinegar is a mild acid and might not want to use on certain surfaces and newer washers. My washer is old and falling apart so I don't care.
squirm
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Re: Slight Sewer Gas smell coming from bathroom

Post by squirm »

Duct tape around the bottom of the toilet to the floor, if the smell stops, it's the wax ring.
austriak
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Re: Slight Sewer Gas smell coming from bathroom

Post by austriak »

I had this issue a couple years ago. Pulled toilet up and it turned out that the flange was broken.

If you are smelling sewer, it is going to be your toilet. If you feel comfortable doing it, pull the toilet up and inspect. Otherwise, hire someone to do it.
Silverado
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Re: Slight Sewer Gas smell coming from bathroom

Post by Silverado »

squirm wrote: Fri Mar 05, 2021 4:20 pm Duct tape around the bottom of the toilet to the floor, if the smell stops, it's the wax ring.
Awesome trick! Beats crawling around sniffing.
cheapedy
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Re: Slight Sewer Gas smell coming from bathroom

Post by cheapedy »

A note about wax rings. I recommend avoiding those which have rubber attached on the bottom. Instead, just double up two of the plain old standard wax rings when installing your toilets. This bit of information was given to me by my dad's friend who's worked as a flooring installer for over 30 years. He says the wax separates from the rubber part as it hardens during cooler temps, thus allowing leaks and odors to get through.
Chip
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Re: Slight Sewer Gas smell coming from bathroom

Post by Chip »

I learned in another thread here that there are alternatives to the wax rings. The main attraction for me is that they don't require that the toilet base be set perfectly on the first try. I used this one on a recent toilet installation. So far, so good.

By the way, we had a wax ring leak with no smell.
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Sandtrap
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Re: Slight Sewer Gas smell coming from bathroom

Post by Sandtrap »

Teague wrote: Fri Mar 05, 2021 1:30 pm Depending on the type of flooring, and the toilet installation, could be a leaky wax ring with some foul water hidden under the vinyl or other flooring material.

For this reason, when installing a toilet I leave a 1 inch gap at the back side when caulking around the base. That way a water leak is more likely to become apparent as it leaks out on top of the flooring. If the base is sealed all the way around water can accumulate occultly and cause the issue you describe, and other problems.
+1
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Teague
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Re: Slight Sewer Gas smell coming from bathroom

Post by Teague »

Sandtrap wrote: Sat Mar 06, 2021 6:35 am
Teague wrote: Fri Mar 05, 2021 1:30 pm Depending on the type of flooring, and the toilet installation, could be a leaky wax ring with some foul water hidden under the vinyl or other flooring material.

For this reason, when installing a toilet I leave a 1 inch gap at the back side when caulking around the base. That way a water leak is more likely to become apparent as it leaks out on top of the flooring. If the base is sealed all the way around water can accumulate occultly and cause the issue you describe, and other problems.
+1
Outstanding!

Tricks of the trade.

j :D
:happy A plumber helping me with my first toilet taught install me that one. Another tip he shared was to use pennies, the older ones make of solid copper alloy, as leveling shims. Wood shims would eventually rot but the copper shims would last almost forever even if wet.
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Topic Author
Brewman
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Re: Slight Sewer Gas smell coming from bathroom

Post by Brewman »

Thank you all for the replies and suggestions!
Once the weather warms a little I plan to check the vent stack first, then the duct tape around the base :D. I have a feeling it could be a cracked flange but hopefully maybe it will only need a new wax ring or double wax ring!

Thanks guys :sharebeer
RuralLivin
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Re: Slight Sewer Gas smell coming from bathroom

Post by RuralLivin »

Years ago, I saw a manager at work pouring water into floor drains at work in the restroom. There was a slight odor of sewer gas in the restroom.

He mentioned all toilets, showers, bath tubs, etc., have the P-trap and the water in them will slowly evaporate if they are not used on a regular basis. As the water evaporates, small opening may let the sewer gas vent into the room. In our house, I'll go around and flush the toilet, run the bathtub/shower, and sink for a bit to add water to the trap.

I had noticed the odor in my daughter's bathroom when she went to off to college. A little water down the fixtures solved the problem.
MarkerFM
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Re: Slight Sewer Gas smell coming from bathroom

Post by MarkerFM »

cheapedy wrote: Fri Mar 05, 2021 11:12 pm A note about wax rings. I recommend avoiding those which have rubber attached on the bottom. Instead, just double up two of the plain old standard wax rings when installing your toilets. This bit of information was given to me by my dad's friend who's worked as a flooring installer for over 30 years. He says the wax separates from the rubber part as it hardens during cooler temps, thus allowing leaks and odors to get through.
A young plumber taught me this trick also. Another thing he did was put them in hot water to soften them up, then he kind of squeezed them together before installing. Not sure if that's necessary, but can't hurt so long as you don't make it out of round.
Teague
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Re: Slight Sewer Gas smell coming from bathroom

Post by Teague »

Brewman wrote: Sat Mar 06, 2021 12:47 pm Thank you all for the replies and suggestions!
Once the weather warms a little I plan to check the vent stack first, then the duct tape around the base :D. I have a feeling it could be a cracked flange but hopefully maybe it will only need a new wax ring or double wax ring!

Thanks guys :sharebeer
If it's a cracked flange they make replacement flanges to fit in the existing pipe which have a flexible seal, and those seem to work. Of course you have to get the old flange out of the way to make room for a new one. For this I learned using a Sawzall at an angle is the precision instrument of choice.

:sharebeer
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furb
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Re: Slight Sewer Gas smell coming from bathroom

Post by furb »

If there is a piece of thread in a trap or anything that can absorb water it can wick out the water that sits in the trap and allow gases through.
Base Hit
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Re: Slight Sewer Gas smell coming from bathroom

Post by Base Hit »

I just dealt with this issue at work and it turned out to be a dead mouse in the wall. It smells very similar to sewer gas and is very difficult to find. Plumber said wax ring was unlikely, because there was no water around the toilet base.
Californiastate
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Re: Slight Sewer Gas smell coming from bathroom

Post by Californiastate »

I've used a lit match to find a poorly installed bowl wax gasket. I passed the lit match around the base of the bowl and watched the flame. The flame would flicker when it neared the bolt holes. The restroom had a strong exhaust fan and not enough make up air. You could hear it as you closed the restroom door. The building was adjacent to the city waste water management plant. For that the city sewer was extremely rancid. I DON'T RECOMMEND USING A FLAME TO FIND METHANE.
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StevieG72
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Re: Slight Sewer Gas smell coming from bathroom

Post by StevieG72 »

A family friend had this issue in a seldom used bathroom. The culprit was the toilet was not being flushed enough, I guess somehow the drain dried out from not being flushed. She now uses / flushes that toilet more frequently and the problem is gone. This is a newer construction home and the toilet appears to be installed correctly.
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Topic Author
Brewman
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Re: Slight Sewer Gas smell coming from bathroom

Post by Brewman »

Teague wrote: Sat Mar 06, 2021 7:15 pm If it's a cracked flange they make replacement flanges to fit in the existing pipe which have a flexible seal, and those seem to work. Of course you have to get the old flange out of the way to make room for a new one. For this I learned using a Sawzall at an angle is the precision instrument of choice.
Thanks I was not aware of this for a flange!
Base Hit wrote: Sun Mar 07, 2021 9:47 am I just dealt with this issue at work and it turned out to be a dead mouse in the wall. It smells very similar to sewer gas and is very difficult to find. Plumber said wax ring was unlikely, because there was no water around the toilet base.
Nope, not a dead mouse. I unfortunately am very familiar with that smell, we have had more than our share in attic adjacent to the master closet :annoyed
Topic Author
Brewman
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Re: Slight Sewer Gas smell coming from bathroom - Problem solved -maybe!

Post by Brewman »

OP here

Edited my original post and it appears, for now anyway, to be resolved! :D
ubermax
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Re: Slight Sewer Gas smell coming from bathroom - Problem solved -maybe!

Post by ubermax »

Years ago sewer gas leaked into the house of my childhood , ignited and blew the walls out - maybe today's homes have safeguards in place or possibly the OP didn't have sewer gas ??
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gwe67
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Re: Slight Sewer Gas smell coming from bathroom - Problem solved -maybe!

Post by gwe67 »

You can also get wax-free (or waxless) toilet seals. Looks like they have many advantages over the old wax seals.
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