Shower drain smell that no one can fix!

[Rafterman]

Hello all. My wife and I live in the coastal area of southeast North Carolina, about a mile from the Intracoastal Waterway. We moved into our new house in February of last year. It has a poured concrete raised slab foundation. We have county water, with a private company managing the sewage for our area. Since about the middle of last summer, we've had a smell occasionally coming from our master bathroom shower drain, which is located on the ground floor. It's not a raw sewage smell, but almost like "sewage light" if you get what I mean. It's not a "rotten egg" sulfur smell either. The shower is a standard 5-foot size with a fiberglass pan in the bottom and tile walls. The smell only comes from the shower drain after you've been in there with the water running for about 5-7 minutes, but then it will stay until about 5-10 minutes after you're done showering. The smell does not occur every time we take a shower though, which is quite puzzling and frustrating. Sometimes we can shower for days without the smell, but then it'll come back. After coming back, it'll smell during every shower for anywhere from a day to a week before going way again. Sometimes the smell is light and sometimes it's so heavy it'll knock you over. The smell is 100% coming from the shower drain itself, and is not being brought into the bathroom via the HVAC system.

We had the plumbing company that worked on our house do a smoke test last September and it was negative. None of our p-traps were dry, including the one for the shower in question. The plumber and I looked all over the house for the sight or smell of smoke, including in the attic, and found nothing. Unfortunately, we were not able to replicate the smell for the plumber at that time (of course.) He said that with a negative smoke test, there was nothing else he could do and left.

Fast-forward to February of this year, and we had the builder's warranty guy come out to fix some other minor issues before we hit our one year mark in the house. We mentioned to him that the shower smell was still present, yet sporadic. He contacted the plumbing company again, who came out and did another smoke test just this morning, which was negative. The plumber said that there was nothing he could do moving forward since the smoke test was negative, and would have the owner of the company reach out to us to discuss any other potential options.

An internet search for "shower drain smell" returned tons of possibilities and solutions. Some articles said the smell was produced by bacteria that feed on the shampoo and soap residue in your pipes. Others said the smell could be due to a dry trap somewhere in the house (again, ours are all wet.) Even others said the smell could be from a toilet somewhere in the house, with the gases coming through our shower drain. However, how could this happen without a dry p-trap? We've tried pretty much every solution we could find, and poured it down the shower drain, including Liquid Drano, vinegar with baking soda, and pure boiling water. NOTHING we've tried has worked. We tried using different shampoo and body wash since they're all made with varying chemicals. Didn't work. The longest we were able to make the smell go away was a little over two weeks before it came back again. I even climbed up on our roof to check the vents up there since one article said that birds or debris could get stuck in the vent pipe and cause the smell, but all the vents were clear.

My wife was literally in tears this morning as the plumber told us there was nothing more he could do since the smoke test was negative. I asked him with the builder paying for all this, why don't they tear up our shower pan for a closer look? He said he can't even be sure that's where the source of the smell is.

This is our pre-retirement home that we plan to live in for at least the next 15-20 years. We can not and will not live with a shower smell for the next two decades. There MUST be some logical explanation for this, but we are at our wit's end and losing hope. If you, or someone you know has ever experienced and/or more importantly fixed a problem like this, PLEASE share what happened and how it was remedied. We are desperate. Please help us solve the problem no one can seem to fix!

 

[CT18]

Have them try mint instead of smoke. sometimes the leak is small and the smoke wont show up. The mint is strong and should be able to smell it if there is an issue. I believe its mint, the plumber should know. I do mostly industrial work, but i do know there another test beside smoke

 

[Twowaxhack]

I certinly agree with the mint test. I use it as well and it’s more effective than smoke in a situation such as this.

Now......Do you get this smell at any other time other than when you shower ?

I have seen a showers that the gel coat leaks and water stays under it trapped in the fiberglass of the pan. When you’d walk around in the pan and get it warm it would stink.

Does your water get treated with chlorine ?

How hot is your water ?

 

[Jeff Handy]

Is there another shower you can use for a few weeks?

If so, can you cover the master shower drain to make it stink tight?

Then wait to see if you still get the stink problem.
Also, has anyone run a camera down the shower drain all the way to the street?

Maybe there is a break or a bad coupling, and stink water is pooling under the slab.

You could also flush some tracer dye down your toilets and other fixtures, and watch to see if the water in the shower trap turns that color.

Do you have an attic, and was that checked during the smoke test?

Just some goofy ideas, maybe they will help.

 

[Twowaxhack]

I see you have county water. I bet it doesn’t have much chlorine in it .

Get your water tested. If it’s not a drain or the shower itself then it’s the water.

There are several things to remedy this if it’s the water. Maintained Chlorine injection to anode swaps and one time high temp chlorine treatment

 

[LIBERTYNY]

It sounds like your plumber is just bowing out of the situation by doing a smoke test and nothing more, Like said above their not always accurate.
You said you have a hvac system ? Check the condensate pressure line and tank they often sink, and a leak would be unlikely to show on a smoke test. Also check anywhere a condensate pump pressure line could leak (including where if they tie into the DWV).
Sometimes things like the wind direction, can leak into the home causeing different drafts making diagnosis difficult.

 

[Rafterman]

Now......Do you get this smell at any other time other than when you shower ?

I have seen a showers that the gel coat leaks and water stays under it trapped in the fiberglass of the pan. When you’d walk around in the pan and get it warm it would stink.

Does your water get treated with chlorine ?

How hot is your water ?

The smell will ONLY occur a few minutes into a shower. We tried to replicate the smell for the builder's warranty guy last summer and were unable to do so. We've also been unable to replicate it for the plumbers when they were here. Naturally, when someone other than us is here, we can't get it to smell. We've had several family and friends visit and stay with us over the last year, and none of them ever smelled anything coming from the other two showers in the house.

I believe our water does get treated with chlorine, yes. You can smell it in the water a handful of times a year when they boost the levels of it.

Our water is set to 125 deg Fahrenheit at the water heater, which is a hybrid electric model.

 

[Rafterman]

Is there another shower you can use for a few weeks?

If so, can you cover the master shower drain to make it stink tight?

Then wait to see if you still get the stink problem.
Also, has anyone run a camera down the shower drain all the way to the street?

Maybe there is a break or a bad coupling, and stink water is pooling under the slab.

You could also flush some tracer dye down your toilets and other fixtures, and watch to see if the water in the shower trap turns that color.

Do you have an attic, and was that checked during the smoke test?

Just some goofy ideas, maybe they will help.

There are two other showers in the house we can use, one on each of the two floors. No one has put a camera down the line yet. I asked the plumber on both occasions if they would try the camera, and the stated both times that since the smoke test was negative, there was no need to do the camera, even though I asked them to do it specifically.

We have thought about trying the dye trick, but have not yet done that. If smelly water is pooling somewhere under the slab though, why would it smell for a day to a week at a time, then go away for as many as two weeks? Wouldn't pooling water produce a smell constantly?

We do have an attic, and it was checked during the smoke test. Both myself and the plumber were up there with flashlights looking and smelling for the smoke.

 

[Rafterman]

I see you have county water. I bet it doesn’t have much chlorine in it .

Get your water tested. If it’s not a drain or the shower itself then it’s the water.

There are several things to remedy this if it’s the water. Maintained Chlorine injection to anode swaps and one time high temp chlorine treatment

I highly doubt it's the water. None of our other neighbors are having this issue we are, and again, it's not a constant smell, only occurring every so often, which makes it so hard to reproduce so that someone other than us can smell it.

 

[Rafterman]

It sounds like your plumber is just bowing out of the situation by doing a smoke test and nothing more, Like said above their not always accurate.
You said you have a hvac system ? Check the condensate pressure line and tank they often sink, and a leak would be unlikely to show on a smoke test. Also check anywhere a condensate pump pressure line could leak (including where if they tie into the DWV).
Sometimes things like the wind direction, can leak into the home causeing different drafts making diagnosis difficult.

At this point in time, we are quite irritated at the plumber and do feel like they're just bailing on us. The builder is paying for their service too, so I'm surprised they're not willing to do more to remedy the situation. The guy literally said to me this morning "I understand your frustration, but if there's no smoke coming out anywhere, I don't know what else to do." I mean, really? I was like YOU'RE the pro, so think of something here!

I'll look into the HVAC being the cause of the issue, but if that was it, wouldn't the smell be more consistent? Wouldn't it likely come from other sources besides the shower?

I think the most frustrating part of this whole thing is that our shower's p-trap is wet, so WHY is there a smell coming from it at all? Isn't that the whole point of a p-trap in the first place?

 

[Twowaxhack]

I highly doubt it's the water. None of our other neighbors are having this issue we are, and again, it's not a constant smell, only occurring every so often, which makes it so hard to reproduce so that someone other than us can smell it.

Do the peppermint test. It’s the cheapest and easiest way to eliminate or prove a breach in the drainage or vent system.,

We could what if all day and night. That’s the next step.

If the peppermint fails to identify the issue then I would conclude the smell was on the house side of the drainage system.

That would include the shower base itself and under it, and it would include the water supply, focusing on the hot water.

It’s imperative that each test be performed correctly.

At the end of the peppermint test before water is used any place in the home, I want you to run water in that shower for the period of time and see if you smell peppermint.

 

[Twowaxhack]

You can do the peppermint test yourself if you can safely walk around on the roof or know someone who can.

Pour a few ounces of peppermint oil down every plumbing stack and chase it with a quart of warm water.

You can buy pure peppermint oil at any health food store or GNC. Or buy off ebay. That’s what I do.

The peppermint oil and the person who pours the oil should never enter the residence while the test is going on.

 

[Twowaxhack]

I wouldn’t be surprised if there’s a big pool of dirty water standing under your shower base on the house side of the trap above the slab.

Take your drain cover off the shower and take some good pics.

take some of the base from a distance. Show me !

Does the shower flex at all around the drain ?

Also I’ve had people complain of stinking showers and it ended up being their sour bath towels hanging in the humid hot bathroom when it would steam up.,

Also had some one complain about a stink in the shower after painting the bathroom......The humid bath would mix with something in the paint off gassing and make a funky Oder.
It started the day they painted and went away after a few weeks.

 

[Rafterman]

I wouldn’t be surprised if there’s a big pool of dirty water standing under your shower base on the house side of the trap above the slab.

Take your drain cover off the shower and take some good pics.

take some of the base from a distance. Show me !

Does the shower flex at all around the drain ?

Also I’ve had people complain of stinking showers and it ended up being their sour bath towels hanging in the humid hot bathroom when it would steam up.,

Also had some one complain about a stink in the shower after painting the bathroom......The humid bath would mix with something in the paint off gassing and make a funky Oder.
It started the day they painted and went away after a few weeks.

I talked with my wife about all the feedback everyone has given us on here today and we are now leaning towards (and hoping that) the problem is water being trapped under the shower pan.

If that is indeed the issue, it would explain multiple things:

1) Why we can even smell the stink at all, despite the shower trap being wet.
2) Why multiple smoke tests have produced nothing coming from the shower drain (because the smell isn't coming from the pipes!)
3) Why the smell is not constant, and will come and go for days or weeks at a time.
4) Why we couldn't reproduce the smell for anyone else. We only ran the shower, and no one actually stood in the shower and walked around on the pan in order to squeeze out the smelly water.

I'll get some good pics on here tomorrow before lunchtime if possible.

 

[Twowaxhack]

I talked with my wife about all the feedback everyone has given us on here today and we are now leaning towards (and hoping that) the problem is water being trapped under the shower pan.

If that is indeed the issue, it would explain multiple things:

1) Why we can even smell the stink at all, despite the shower trap being wet.
2) Why multiple smoke tests have produced nothing coming from the shower drain (because the smell isn't coming from the pipes!)
3) Why the smell is not constant, and will come and go for days or weeks at a time.
4) Why we couldn't reproduce the smell for anyone else. We only ran the shower, and no one actually stood in the shower and walked around on the pan in order to squeeze out the smelly water.

I'll get some good pics on here tomorrow before lunchtime if possible.

I completely agree. The smoke test probably wouldn’t find a small leak tho. Not a good test for your problem, IMO.

 

[MarianneR]

Your assumption that the building and the plumber are independent entities is misguided; the builder hires the plumber to not find anything wrong. I'd invest in a 2nd opinion from an independent plumber.

Its like when you buy Real Estate NEVER use the inspector they recommend. They recommend people who don't find anything wrong because they don't want problems with the sale. They're not working for you.

 

[Riickk]

Your assumption that the building and the plumber are independent entities is misguided; the builder hires the plumber to not find anything wrong....

Its like when you buy Real Estate NEVER use the inspector they recommend... because they don't want problems with the sale.

100% in both cases. Inspector on my house was either deliberately blind-in-both-eyes, or whose strength lay in buying BUILDING INSPECTOR business cards.
In order to look unbiased, classy Realtors might recommend 3 different go-to-guys (or gals); none of them will ever find significant defects, unless you're in danger of walking into house, slipping, and rolling downhill to the far wall of next room. Two sleazy businesses.
/

OP ...it's not that they can't fix the problem, THEY HAVEN'T TRIED TO FIX ANYTHING.
Instead, knowing the problem isn't there *today* (or they'd smell it) they did a smoke test and found nothing, then returned, to do a second moke test, with same results. What a surprise! Did he the problem fixed itself, spontaneously?
He can't run a camera down the drain line? No, he's unwilling to use a camera. Why not?; Because it might show there's a problem - one that's expensive for the builder to fix. Do you think he'd hesitate to use a camera, if you'd hired him, and asked him to do so? He might tell you wasted money, but he'd dig in to find the source of the problem.

 

[MarianneR]

100% in both cases. Inspector on my house was either deliberately blind-in-both-eyes, or whose strength lay in buying BUILDING INSPECTOR business cards.
In order to look unbiased, classy Realtors might recommend 3 different go-to-guys (or gals); none of them will ever find significant defects, unless you're in danger of walking into house, slipping, and rolling downhill to the far wall of next room. Two sleazy businesses.
/

I asked my realtor for references so I knew who NOT to hire. He was quite surprised when I hired a hard ass who found a bunch of stuff

 

[MarianneR]

100% in both cases. Inspector on my house was either deliberately blind-in-both-eyes, or whose strength lay in buying BUILDING INSPECTOR business cards.
In order to look unbiased, classy Realtors might recommend 3 different go-to-guys (or gals); none of them will ever find significant defects, unless you're in danger of walking into house, slipping, and rolling downhill to the far wall of next room. Two sleazy businesses.
/

OP ...it's not that they can't fix the problem, THEY HAVEN'T TRIED TO FIX ANYTHING.
Instead, knowing the problem isn't there *today* (or they'd smell it) they did a smoke test and found nothing, then returned, to do a second moke test, with same results. What a surprise! Did he the problem fixed itself, spontaneously?
He can't run a camera down the drain line? No, he's unwilling to use a camera. Why not?; Because it might show there's a problem - one that's expensive for the builder to fix. Do you think he'd hesitate to use a camera, if you'd hired him, and asked him to do so? He might tell you wasted money, but he'd dig in to find the source of the problem.

People think "warranty" work is like at a car dealership; the dealership makes money off of warranty work, so they're eager to fix any little thing. That's not the case with builders. They set aside money for repairs, but they want to do as little as possible.

 

[Twowaxhack]

Your assumption that the building and the plumber are independent entities is misguided; the builder hires the plumber to not find anything wrong. I'd invest in a 2nd opinion from an independent plumber.

Its like when you buy Real Estate NEVER use the inspector they recommend. They recommend people who don't find anything wrong because they don't want problems with the sale. They're not working for you.

If a builder that I did a job for is having problem with the plumbing you can bet no matter who’s paying me that I’m trying to find the problem.

Does that mean the guy is knowledgeable enough to find it ? No

The op even said that when other people are there he can’t recreate the smell.

Sometimes it hard to find a ghost......

Plus I have an insurance bond that will pay if I cause a problem that must be repaired by others.....then if I was found to be negligent I would be subject to subrogation.

Have any idea what subrogation means ? Look it up. So yes, I have every intention to find my problems if I have one.

If this ever went to court they could sue the plumber and the builder. The plumber does not work under the contractors umbrella.