Shower drain smell that no one can fix!

Help Support Plumbing Forums:

Twowaxhack

Professional
Professional
Joined
Feb 9, 2021
Messages
4,925
Reaction score
2,213
Location
United states
If I had a smell that I couldn’t find and I had a couple people on a forum suggest using peppermint as a great way to locate Oder coming from a drainage system, I would immediately have that test carried out.

I have found problems with peppermint where other plumbing companies used smoke and failed.

And guess what ? Other people will smell the peppermint it and document it.

The amount of sewer gas in a system can vary, this can cause the smell to come and go.

It doesn’t matter if the water company uses chlorine and that you can smell it sometimes. We still bleach the system and crank up the water temp. We use a much higher concentration of chlorine.

But the water treatment would be a last resort. The peppermint test would have already been done at my house by now.......
 

Rafterman

Member
Joined
Mar 9, 2021
Messages
14
Reaction score
6
Location
North Carolina
Sounds like you know a lot except for how to find the problem.
Well, I never claimed to be a plumber or to know how to find the problem. If I knew that, then I wouldn't be on a plumbing forum getting advice from the plumbing connoisseurs such as yourself. However, you're not wrong. I DO know a lot of things in general. I'm a programmer by trade, but I know a little bit about plumbing, carpentry, auto repair, flooring, drywall, electrical, painting, and landscaping all thanks to my father and former jobs that I held before starting what is currently a 17-year career in computers. So I'm not a master of anything, but do know enough to make my way in the world.

I have a 2 towels for everyday of the week. I have my priorities and one of them is staying clean.
OK, I was wrong earlier. YOU are clearly the neat-freak. Not me. Using two towels a day just for drying your clean body is uh, how can I put this...obsessive.

If the in-wall camera check fails, I'll definitely do the peppermint test before we attempt to try anything else. I just simply don't have a lot of patience for having to spend the money and do all the detective work and labor of finding the problem with a brand new home that we paid a lot of money for. That's why builders are supposed to stand by their work and back it up. Sadly, that's not always the case nowadays.
 

Twowaxhack

Professional
Professional
Joined
Feb 9, 2021
Messages
4,925
Reaction score
2,213
Location
United states
A peppermint test takes 20 minutes and 20$. But you’ll need access to the roof vents or an upstream cleanout. (Highest point in the drainage).

This will stop your wild goose chase.

I’m posting this for future readers. I don’t expect you to do what I suggest.

It’s the least invasive, most economical and informative test or inspection that can be done at this point. Yet you’re about to remove baseboards. 👍
 

PerplexedPlumber

Well-Known Member
Joined
Aug 9, 2020
Messages
199
Reaction score
68
Location
64801
It sounds odd that the public potable water system is treated intermittently, but that would be a way to minimize exposure to THMs and reduce cost, if it successfully maintains integrity of the system. However, now I would reconsider the potable water, but still don't think it is likely. Something that could be useful would be to learn about the sulfate level in your water. When the plumbing was installed originally, it is possible that soil got into lines and the lines may not have been treated at the point the plumbing was completed. While the house was unused for a period of time, if a biofilm developed inside any lines, it may be difficult to eliminate at this point. And you wouldn't want to over-treat and risk damage to lines or fixtures. So hopefully you will find a cause with one of the two other test methods. And you would have probably noticed a pattern to this already.

Your drain holds water, so bacteria are always present. This is normal, just as there are bacteria everywhere in your environment, and the vast majority do not cause illness. (Sanitizer commercials can stoke fears, but there are reasonable needs and application rates for sanitizers.) The type of bacteria that grow depend on the nutrients available. You could even find that a shampoo that you use occasionally contains sulfates. But putting your nose that close to a drain, I would think it would always stink. If hydrogen sulfide is present, however, you will smell it in an enclosed room, but not necessarily at the point of origin.

There is one trait that plumbers, mechanics and programmers share: a passion for problem-solving. Not everyone values humility, or even respect. But they can still have good input when you cut through the fluff. Or bristles.

Chasing down the cause of an intermittent odor can end up being expensive, and since people don't want to admit failure or risk being liable, sometimes they will offer some explanation but they may attribute it not to reality but to the owner. The source of intermittent odors can be difficult to identify, so this becomes a sort of skills test. It's like an intermittent electrical problem in your car. It started at a specific point after a repair, and several returns later or to multiple shops, it may be resolved. Hang in there.
 
Last edited:

Twowaxhack

Professional
Professional
Joined
Feb 9, 2021
Messages
4,925
Reaction score
2,213
Location
United states
Chlorine levels vary in the water supply due to varying rainfall levels. I believe it’s when there’s a lot of rain they use more chlorine.
 

Rafterman

Member
Joined
Mar 9, 2021
Messages
14
Reaction score
6
Location
North Carolina
A peppermint test takes 20 minutes and 20$. But you’ll need access to the roof vents or an upstream cleanout. (Highest point in the drainage).

This will stop your wild goose chase.

I’m posting this for future readers. I don’t expect you to do what I suggest.

It’s the least invasive, most economical and informative test or inspection that can be done at this point. Yet you’re about to remove baseboards. 👍
I'm not removing anything. The builder is removing our baseboards and also replacing and recaulking them, at $0 charge to us, as it should be. Besides, it's baseboard behind our washer and dryer in the laundry room. No one ever sees it. A peppermint test may end up being the "miracle cure" for finding the source of the smell, but we have to pay for that (as inexpensive as it may be), and I've already been up on the roof once to check the vents. Like I said, if the camera in the wall finds nothing, then I'll spend the $20 and head back up on the roof. At least we have a 1.5 story and not a true 2 story. Much less worrisome for my wife to watch me go up a 16 foot ladder instead of a 32 foot. I had to do that once at a previous home to repair some 2nd story flashing that blew off in a hurricane. Not fun.

There is one trait that plumbers, mechanics and programmers share: a passion for problem-solving. Not everyone values humility, or even respect. But they can still have good input when you cut through the fluff. Or bristles.

Chasing down the cause of an intermittent odor can end up being expensive, and since people don't want to admit failure or risk being liable, sometimes they will offer some explanation but they may attribute it not to reality but to the owner. The source of intermittent odors can be difficult to identify, so this becomes a sort of skills test. It's like an intermittent electrical problem in your car. It started at a specific point after a repair, and several returns later or to multiple shops, it may be resolved. Hang in there.
We're trying to stay positive about this. Honest we are. Being a problem-solver, it burns me up not knowing what this is. I just want an answer at this point, no matter how simple or difficult the fix might be. I'd rather the builder say "well, we found the issue, but fixing it means tearing up your master bath for a few weeks as we dig into your foundation" as opposed to "sorry, we can't figure it out either, but good luck with everything and enjoy your home!"
 

Twowaxhack

Professional
Professional
Joined
Feb 9, 2021
Messages
4,925
Reaction score
2,213
Location
United states
If I can do a test that doesn’t require a hammer, nail puller, caulk. And will give me a lot of info for $20 and 30 minutes of my time then I usually take it.

I do the least invasive checks and tests first when I’m chasing a mystery.

But sure, if they want to come into your home and look them Im not saying stop them. I’m just a nobody on a forum.
If you’re getting free service then you don’t have much choice in how they choose to proceed.

I would certainly make the suggestions that myself and others here on this thread have suggested known to the men investigating your problem.

Just keep what I say in your pocket, it may be helpful to you before this plays out..
 

plumbmatt88

New Member
Joined
Sep 6, 2019
Messages
2
Reaction score
3
Location
Australia, Queensland
In Australia, it is common for the shower drain to discharge into the floor drain riser which can cause smells to come out of floor waste drain during showers. To help control this a one way ‘odour device’ is inserted inside floor riser which allows water to still drain down but stop air from rising.
second most common is a worn rubber seal around toilet bowl waste connection near floor. When seal is worn it won’t leak but does let sewer gases escape drains especially while using a nearby fixture.
Also check shower and basin drain for hair build up. Vinegar and bi carb is good for cleaning out drains.
 

Attachments

FishScreener

Well-Known Member
Joined
Aug 23, 2018
Messages
557
Reaction score
203
Location
83467
A comment on Chlorine Levels: The free chlorine levels are pretty tightly controlled. We try to keep our systems at between 0.5 and 1-ppm of free chlorine at all times.

You can’t actually smell free chlorine. What you typically smell is the daughter chemical compounds that results when the free chlorine reacts with contaminants in the water.

So, after it rains,they have to boost up the total chlorine to have the target for free chlorine left after it reacts with what is in the feed water.
 

Twowaxhack

Professional
Professional
Joined
Feb 9, 2021
Messages
4,925
Reaction score
2,213
Location
United states
Different parts of a municipal water system will have different chlorine levels.

It might all be the same when it leaves the treatment plant but what you get at your tap may be different.

Potable water systems routinely get breached. No telling what’s in your water.

Years ago some contractor connected a neighborhoods forced sewer main to the potable water main.
About a year later after multiple complaints it was found.

I remember when this happened. It was about 16 yrd ago.
 
Last edited:

Twowaxhack

Professional
Professional
Joined
Feb 9, 2021
Messages
4,925
Reaction score
2,213
Location
United states
My potable water bounced from 7.5ph to 10.5 ph. Usually it’s around 8. Low TDS of around 90. No complaints, I’m a long way from the treatment plant on a main that doesn’t get a lot of flow.

I have a small fish pond so I check my water before and after I treat it.
 

PerplexedPlumber

Well-Known Member
Joined
Aug 9, 2020
Messages
199
Reaction score
68
Location
64801
My potable water bounced from 7.5ph to 10.5 ph. Usually it’s around 8. Low TDS of around 90. No complaints, I’m a long way from the treatment plant on a main that doesn’t get a lot of flow.

I have a small fish pond so I check my water before and after I treat it.
I can't imagine a circumstance where potable water would have a pH of 10.5 unless it were contaminated. That sounds like an ammonia contamination to me. pH increase can occur from bacterial activity on nitrogen sources in standing surface water, but that is a high pH. If you are using a meter, consider getting some test strips to check the meter.
 

Twowaxhack

Professional
Professional
Joined
Feb 9, 2021
Messages
4,925
Reaction score
2,213
Location
United states
I can't imagine a circumstance where potable water would have a pH of 10.5 unless it were contaminated. That sounds like an ammonia contamination to me. pH increase can occur from bacterial activity on nitrogen sources in standing surface water, but that is a high pH. If you are using a meter, consider getting some test strips to check the meter.
I have strips, liquid and a two point calibrated test meter.

We’re all probably being poisoned 🤣
 

PerplexedPlumber

Well-Known Member
Joined
Aug 9, 2020
Messages
199
Reaction score
68
Location
64801
I have strips, liquid and a two point calibrated test meter.

We’re all probably being poisoned 🤣
Well, yes, but that is beside the point. ; )

Have you checked with your local water resource group to see what the typical range is for your area?
 

Twowaxhack

Professional
Professional
Joined
Feb 9, 2021
Messages
4,925
Reaction score
2,213
Location
United states
Well, yes, but that is beside the point. ; )

Have you checked with your local water resource group to see what the typical range is for your area?
They be send out a report and they say it’s usually around 8. It’s usually at 7.5-8 but I’ve had it test high in small amounts of water.
💀
 

Rafterman

Member
Joined
Mar 9, 2021
Messages
14
Reaction score
6
Location
North Carolina
Well, we finally got this problem resolved! Sorry it took me seven months (!) to update this thread with the solution. I had completely forgotten about it all summer. Apologies for the long post, but we went through an awful lot to get this resolved!

Last time I posted in here, the warranty guy from the builder was coming over to remove the baseboard in our laundry room and check under the shower pan for leaks. Well, that produced no results. It was completely dry under the pan. A few weeks after that, we called a completely different plumber here in town, explained the situation to them, and had them come over. They performed their own smoke test, but did it differently than the builder's contracted plumber. The one we hired took some pool noodles wrapped in towels and used them to plug our main drain pipe via the clean out lid out by the street near the front of our lot. That clean out is about 70+ feet from the cleanout they put the smoke into. That one's right in front of the house, hidden under some hedges. The result was a crazy amount of smoke coming out our two roof vents, something we never noticed when the builder's plumber did their two smoke tests during previous visits. This was likely because they never plugged the main pipe at the clean out by the street!

One of our roof vents exits out into a totally open section of shingles with nothing above it or around it. However, the other vent was located very close to a wall, and 2 feet underneath a soffit vent (see attached photo.) When the plumber we hired went into the attic with a flashlight and looked around, he located smoke that was coming in via the soffit vent. However, since no smoke came in through any shower, toilet or sink in the house, the plumber suggested that our shower drain was smelling due to insufficient ventilation to the outside air. He said that with five drains in our master bathroom (shower, corner tub, two sinks, and a toilet), the single vertical vent was not capable of handling all that, and they would possibly need to add a second vent in our master bathroom that lead up to the roof. Now, our foundation is poured concrete slab, not a crawl space. The plumber's loose estimate for digging into our foundation and adding the additional drain was anywhere from two to five thousand dollars. To his credit, he did suggest we ask the builder to move the vent located under the overhang first to see if that would fix the issue, since that was the cheapest solution. Plus the fact that the vent never should have been in that location to begin with.

Now that we had gotten another plumber's opinion and another smoke test (at a cost of $485), we took this information to the builder. They shared all this with the original plumber, and together agreed that another visit to our house was necessary. So right around the start of summer, we had the owner of the original plumbing company, as well as the chief construction guy from the builder (can't remember his exact title) come over at the same time. Both of them agreed that the roof vent was poorly located and never should have been installed there in the first place. The plumber agreed to move the vent further up the roof, and the builder would have the roofing company come seal the old vent hole and install the lead boot over the new vent, all free of charge. Remember that our original bumper-to-bumper warranty on the house had expired at the end of February. However, since there was a long-standing record of us complaining about the smell for many months, they agreed to fix everything at no cost to us. Also, the owner of the plumbing company voluntarily offered to fully reimburse us the $485 we had paid to have a smoke test and assessment done by the other company.

Next, I discussed with them the other plumbing company's plan to dig into our foundation in order to add another vent. The plumbing owner told me that our roof vent pipe was definitely large enough to handle one half of our house. He said it's possible the lead boot could have been poorly folded over the top of the PVC when it was originally done, thus blocking some of the air flow. Since the the pipe was getting moved further up the roof anyway though, the builder's construction guy said he would make sure the roofing company did a clean job when they came to install the new lead boot.

Finally, the builder's guy asked me what water heater we had. I told him it's a State brand hybrid electric heat pump (link). He asked me if I had flushed it yet since we moved in and I told him no. He said that there had been a few other homeowners in houses built by their company that were having issues of smelly water coming from this particular brand/type of water heater. So, he and the plumbing company owner said that in addition to relocating the roof vent, they were going to drain our water heater and do a complete chlorine flush of our entire plumbing system.

A few weeks later, we had a new roof vent, a clean water heater, a completely flushed plumbing system, and NO MORE SMELL! After many months of a smelly shower and bathroom sinks, plus endless frustration, we finally were able to put this issue to rest and enjoy our home again.

The last bit of advice the two of them left me with was to completely drain our water heater once a year (after turning off its circuit breaker), and to pour a little splash of bleach in our master bathroom sinks and shower drain, then let it sit overnight before flushing in the morning. They recommended we do that every four to six months.

Whew, what a mission. But we're finally free!
 

Attachments

Last edited:

Twowaxhack

Professional
Professional
Joined
Feb 9, 2021
Messages
4,925
Reaction score
2,213
Location
United states
I say it was the water heater. That’s when the stinky water vapor in the room was high and that’s why you only smelled it when the shower was being used.

If it was the roof vent you would’ve smelled it at other times as well, not just when the shower was being used.
That roof vent should’ve never passed code.

That’s my opinion.
 

Jeff Handy

Pro Handyman, NOT A Pro Plumber
Joined
Jul 5, 2019
Messages
4,585
Reaction score
1,532
Location
Chicago suburbs
That also looks like an exhaust fan vent in the soffit.
Probably from your bathroom.
Vents like that are a poor design, they should go out the roof.
The output from the exhaust fan vent just gets sucked back into the little vent openings in the soffit.
 

Rafterman

Member
Joined
Mar 9, 2021
Messages
14
Reaction score
6
Location
North Carolina
I say it was the water heater. That’s when the stinky water vapor in the room was high and that’s why you only smelled it when the shower was being used.

If it was the roof vent you would’ve smelled it at other times as well, not just when the shower was being used.
That roof vent should’ve never passed code.
I agree it was the water heater as well. Initially, I swore high and low that the smell was coming directly from the shower drain itself because I could stick my nose in the drain and smell it very strong. However, when both our master bath sinks started smelling too, then I knew it was something other than just the shower drain alone. One wall of our master bath is shared with the garage, and just on the other side of that wall is the water heater. We were getting hot, smelly water piped right into our bathroom with no interruptions.

The plumber we hired on our own said he had never seen a roof vent placed that close to a vertical wall, and also never under a soffit like that. Like you, he said it never should have passed. Oddly enough, the inspector we hired before closing on the house, as well as the one we used at the 11-month mark (same guy) never noticed the roof vent being in that position either. It wouldn't have prevented the smell from happening, but should not have been allowed to stay in that location anyway.
 
Last edited:

Rafterman

Member
Joined
Mar 9, 2021
Messages
14
Reaction score
6
Location
North Carolina
That also looks like an exhaust fan vent in the soffit.
Probably from your bathroom.
Vents like that are a poor design, they should go out the roof.
The output from the exhaust fan vent just gets sucked back into the little vent openings in the soffit.
Yep, that's the exhaust vent for the fan in the upstairs bathroom. The vanity mirror is right on the other side of that vertical wall. Thankfully, we only use the upstairs as a sort of guest suite for visitors, so the bathroom rarely gets used.
 
Top