Puzzling case of sewer smell only while showering

[Heidi]

I have a tiled shower in the master bathroom that started smelling like sewer gas (rotten egg/bathroom smell) but only while showering. The shower is used every day. The trap is visible and is working and there are no issues with any of the other drains in the bathroom.

I've had a couple of plumbers out to look at it but all they can really suggest is putting bleach down there. The drain has been cleaned out and there is no debris or gunk down there. The toilet does not gurgle, the wax seal is intact on the toilet, and all traps seem to be functioning in the bathroom.

I've done a lot of reading on this site and elsewhere on the internet but I'm no plumber so I would desperately like some advice on what to do next.

I think it might be one of two things. It might be the lining of shower was laid flat (house was remodeled in 2005) and so water and whatever has collected under it but I can't see how it would create that distinct sewer smell. It is not a musty odor, it smells like sewer.

The other possibility involves some work that was done on a bathroom almost directly below this one. On a Friday in June, the crew reattached the toilet and sink of a downstairs bathroom after doing a fair amount of work in the room. On Saturday, the shower stunk for the very first time. Is it possible that something the plumber did when reconnecting the toilet and/or sink could be causing this by trapping gas in the drain pipe so the gas rushes back up the shower drain when the water comes on?

This is very distressing so I would appreciate any suggestions on what to do or where to look.

[thebigsee]

Just taking a stab at the dark here but is it possible that it is the water coming out of the showerhead that smells? At my brother's house, he gets all his water from a well and if they don't keep the filter maintained properly, the water smells of rotten eggs. Or, if the workers below disturbed your water lines significantly or shut the water off for awhile, it might have resulted in old debris coming out of the lines, which could be trapped in your showerhead.

The pros should weigh-in on this but your p-trap provides a constant water seal -- it's designed to keep odors out. If there's nothing between your drain cover and the water at the bottom of your trap that could be causing odor, it seems to me that it must be related to what is coming out of your showerhead.

[Heidi]

Thanks for the response. I don't think it's coming from the showerhead because the smells wafts up during the shower and also because I have stuck my nose everywhere in that shower that I can reach before, during, and after showering. If my nose knows anything, the smell seems to be coming up from the drain.

If it's not the tile floor issue, then I think when the water is running through the P-trap, it's allowing a little gas to sneak back up but then I don't know how or why it could be doing that.

[thebigsee]

Yes, I was thinking about this over lunch and I hadn't considered the issue of proper venting in my original response. It could be that when the work was done downstairs, they did work on the vent pipe and either didn't properly vent the new pipes they did, or somehow your existing vent pipe has become blocked somehow. That sewer gas has to go somewhere and it sounds like it's pushing up through your drain. Might want to have the vent cleared or inspected. Hopefully one of the expert plumbers will weigh-in on your dilemma soon though.

[jadnashua]

With water running in the shower, the trap would be full...if they messed up the venting, it could siphon dry in between showers, but not during one with the water draining.

The mortar in a tiled shower is naturally somewhat basic. If the liner is not installed on a pre-slope, water will accumulate in the drypack mud (mostly sand with some cement to hold it together). Stuff tends to grow in there only after a few years when soap, body oil, etc, can migrate into that stagnet area and makes the pH closer to neutral or acidic. That can take anywhere from a few years to never depending on use, the quality of the grout and caulking, and the use.

For some other insight on tiled showers, check out www.johnbridge.com.

[Heidi]

Thanks for the link to John Bridge. However, I'm still puzzled as to how it could smell like rotten eggs and sewer when it's coming out through the tile floor. It is very definately not a mildew or rancid drain smell.

Is there any way that a restriction further down the drain could cause a buildup of gas in the pipe that would creep up and out the drain while water is trickling down it? My shower doesn't have much water pressure so it's not like a torrent of water is going down the drain..

[jadnashua]

A shower built with the liner flat on the floor can end up smelling like a swamp. It may not, but it can. If there was positive pressure in the drain system, you'd likely hear the gas bubbling through the trap. It's very unlikely that it's gas bubbling up through the trap.

[Heidi]

It is not the tile, it is something further down the line. We had our toilet in the basement pulled up and the smell from the toilet hole is the exact smell that seeps up in the master shower but only while showering.

The latest expert we had to our house agrees that it must be a restriction of some sort down in the basement bathroom area but is not sure where or where to start to find it. He is suggesting snaking out the main drain down in the basement. Would it be worth it to run a camera down the shower drain to find out exactly what is going on before any further steps? How much would that run?

[kalia]

Hi, Did any of you solve this problem? I have a TERRIBLE sewer gas smell and I have tried everything in this column and then some! I've replaced the p-trap, added a second one, snaked and camered all the lines and all the vents, installed new vents, had smoke tests done, had 4 plumbers look at the problem, cleaned the drains and all the pipes with cleaners and brushes, used bleach, draino, pipe cleaner, pro biotics, replaced my main lateral line, filled the vents with water to detect blockages, opened up all the walls to look for leaks or broken vents -- NOTHING has found the problem! Please help!
The smell comes ONLY after or while running the shower. If I cover the drain and run the water, there is no smell. It's MUCH worse if I uncover the drain and let a large amount of water drain at once. It goes away a little bit if I don't use the shower for a month, but then comes back full force after using it once. Any ideas?

[Dunbar Plumbing]

The dirty arm from trap to vent is scaling with the nasty stuff and when that water enters the drain it's allowing soome smells to come back.

My shower drain does this initially but stops as fast as it starts. When I finally get in there and jet the drain with a garden hose, bringing it back to a clean state, the problem ceases.

Sewer gases can escape while a trap is taking water on. The reference to the shower head was a plausible one as well.

Bacteria growing inside that head and starts smelling as soon as you start using it.

Some really smell horrible when they are not being cleaned.

[johnfrwhipple]

I have been reading about this Chinese Dry Wall complaints.

Seams the smells are intensified by moisture?

Do you know where your drywall came from for the bathroom?

There might be a link here.

or perhaps it this......

I've been working on my exterior deck and stumbled upon a serve smell from the wet tiles. I'm using slate for my deck and it was not the stone that smelled but the glue that held the smaller tiles to a larger sheet of them. This glue and this mesh smell horrible. Since many tiled showers use mesh backing for sheets the smell might very well be your tiles themself or the glue holding them to the sheets.

If you have extra tile try soaking them in hot water for 90 minutes. Do they fall off the sheet or mesh? Place this sheet or mesh in a plastic bag and leave it a day. Take a wiff in the morning. Does it smell like that smell your trying to track down? If so you might have found the answer....

Good Luck.

JW

[plumbergreg]

I have one possible explanation, there is a sag in the shower's trap arm possibly caused by cutting a tee into the stack when they did work in your basement. This could cause the trap to be siphoned and allow brief amounts of sewer gas in. You could always rent a camera and have a look.
Good luck!

[Inspektor Ludwig]

do you know how long the trap arm of the shower is and if it ties into a vertical waste with santee or wye? You also said that it smelled like sewer/rotten egg smell. Did it smell like sulfer? I don't think sewer gas smells like rotten eggs, if it smells like sulfer it might be something other than the drain.

[jay_wat]

there a bathroom fan?

i had a similar deal on a job of mine,,found out that it was the Vent on the roof was near the intake fan for the bathroom,,exteneded the vent up,,and problem solved

[johnfrwhipple]

Inspect one of your electrical plugs our switches nearest to the shower.

Have your wires turned black - this would be a sign of Bad Dry Wall.