Stinky bathroom help

[FireOnTheMuffin]

My hall bathroom underwent what I thought would be a pretty uninvolved plumbing job.  A new vanity was put in.  A new toilet.  And a tub was converted to a shower.  Since then, the bathroom seems to get dead/sewer air accumulating.  While showering, I’ve heard a glug in the shower drain and suddenly a plume of terrible air comes out.  But I’m not confident it’s only the shower.  My husband has claimed it accumulates in/from the sink as well.  For the last 2 winters (actually all year long) we’ve left the window cracked open to avoid the stink.  Luckily I live in a mild climate… but I still had to run the heat last winter cause I had a new born, and this all really irks me.  Plumbers don’t seem to know what’s going on… But the last one suggested I do a smoke test.  However, my experience with the glugging shower (which doesn’t happen every time) makes me worry a smoke test wouldn’t work because the p-trap clearly SOMETIMES holds water.  Please use your superior plumbing brains to help me figure this out!!

[nalor511]

Have you snaked the shower drain? Washer drain? My shower and washer drain into the same main pipe, and when I snaked (using a manual 25' from Amazon) it solved the sewer burps. Since then I use a hair catcher in the drain. No sewer burps for over a year

[MOOVN2MTL]

A partial (vs complete) household sewer pipe blockage would be my first place to look as mentioned. Most likely downstream of the affected water appliances. The sewer pipe system is usually just composed of sewer gas with the exception of the p-trap. I’m presuming using the shower fills up the sewer pipe with water upstream from the blockage displacing the gas upwards and through the p-trap (essentially a very low pressure valve).

[sonofsven]

So each of the drains has a vent as well, usually in a bathroom they're combined into one pipe that goes up and out the roof.
It sounds like a venting problem more than a draining problem.
Make sure nothing is blocking the vent coming out the roof.
You can also run a hose down through the vent and make sure it drains.

[FireOnTheMuffin]

All the bathroom fixtures of my 2 back-to-back bathrooms drain into the same mainline and out of the house.  The kitchen sink is the only fixture that is far away and joins up with the mainline.  I recently had it hydrojetted and scoped and I watched the camera get to the mainline and didn’t see a blockage in that area.  I guess it’s possible there is something at another point in the main line.  I also was up on my roof and snaked all of my vents but felt no blockage, but if the vent line has Ts and elbows out from the roof vent along the way, I haven’t been able to get at them.  I could try snaking the shower drain itself?

[nalor511]

All the bathroom fixtures of my 2 back-to-back bathrooms drain into the same mainline and out of the house.  The kitchen sink is the only fixture that is far away and joins up with the mainline.  I recently had it hydrojetted and scoped and I watched the camera get to the mainline and didn’t see a blockage in that area.  I guess it’s possible there is something at another point in the main line.  I also was up on my roof and snaked all of my vents but felt no blockage, but if the vent line has Ts and elbows out from the roof vent along the way, I haven’t been able to get at them.  I could try snaking the shower drain itself?

If you had the line hydrojetted at a point after the blockage (coming from the shower or clothes washer), this will not help you. Your symptom really sounds like a *partial* blockage or narrowing. I manually snaked my shower and clothes washer, and got a bunch of brown crud, about 20' down, and my sewer burps stopped. And using hair catchers has prevented the problem for a year.

Unless you already use hair catchers, this is where my money is. Hair catchers don't just catch hair, they catch oil/soap and other gunk, and you clean them daily. Amazing what they catch, that would otherwise be lining your drain pipes.

[Frankies Girl]

I had a very sinky sewage poo gas smell that would come up in our bathroom that is closest to the exterior line out of our house. After years of just hoping it would go away, this is what works for us:

1. Hydrojetted entire house due to gunk/clogs further up the line, and had an added bonus of clearing ALL the gunk so we were starting with a pretty decently clear whole house line.

2. NO grease or food waste down the kitchen any more. It gets wiped out and trashed.

3. Check the that the tub trap was maintaining water (it was) so that wasn't the issue.

4. Realizing that this bathroom was used primarily by husband, who sheds tons, and uses lots of soap/oil products so there's more than a usual amount of stuff that will end up in the pipes. That gunk can end up with an over abundance of the bad type of bacterial junk and will also offgas stench in addition to causing slow draining.

5. Started using lye drain cleaner every 6 months or so down any drains we were concerned with. We get it from Walmart or HD, it's cheap, it's non damaging to the pipes as long as you follow directions (don't splash it on yourself or bare skin either). Leave it in there about an hour and then flush the pipes really well. It eats up the hair and greases/oils and turns them basically into (really gross) soap, that will be washed away with the flow of water.
https://www.homedepot.com/p/Instant-Power-Crystal-Lye-Drain-Cleaner-1650/204374017

6. We drop some of these drain refresher sticks down the sink and tub drains monthly. They have lemon scent, but also the good bacterial makeup to eat away any gunk build up.
https://www.homedepot.com/p/Green-Gobbler-Bio-Flow-Drain-Cleaning-and-Deodorizing-Sticks-Lemon-Scent-12-pack-G0885D/313143891

My plumber recommends a monthly dump of a whole bottle of dollar store bleach down any offending pipes (both the ones that get blocked by overgrowth or just stinky) and leaving it overnight and then flushing the next morning, but that will kill ALL the good stuff in the bioflow drain sticks and you also shouldn't do this for any septic systems. It does work somewhat, but it's a less than stellar option and I've only done it a few times over the years when I've forgotten to keep up with the lye/bio sticks for a few months.

Never have had an issue since. You don't have to do the hydrojet if you're not experiencing any blocks/clogs - but it will take care of that and the ick smells too and give you a nice clean slate.

[FireOnTheMuffin]

@nalor511 and @MOOVN2MTL, can you explain why a partial blockage wouldn’t have the gas go up the vents, as @sonofsven suggests?  But, @Frankies Girl, it is similarly the bathroom closest to the exterior line out of the house…. Maybe I do need to try all this.

[nalor511]

@nalor511 and @MOOVN2MTL, can you explain why a partial blockage wouldn’t have the gas go up the vents, as @sonofsven suggests?  But, @Frankies Girl, it is similarly the bathroom closest to the exterior line out of the house…. Maybe I do need to try all this.

I can't explain it, but I did experience it. Clearing and scoping the vents didn't do it for me. Hand snaking did.

[lthenderson]

I agree with sonofsven and that it sounds like a venting problem. Of the three changes, toilet, shower and vanity, my guess would be something about the vanity install is not correct or went wrong. Often times, the vent goes up from the vanity drain and then the shower and toilet vents connect somewhere above that point. If handy, I might remove the trap and look into the vanity drain pipe for blockages and try to snake up the vent from there. I think it would probably be nearly impossible to snake all possible avenues for a blockage from the roof top.

[MOOVN2MTL]

I could be wrong but I believe the vent primarily provides air into the house sewer piping system as water is flowing. If the vent is clogged I would expect you might see a small water level lowering in the toilet p-trap, which is easily observable— or just some water movement in the bowl while water is flowing through the system. I’m not dead set against the vent blockage suggestion. I personally would just start carefully snaking things (vents and pipes) to eventually get to a solution.

[sonofsven]

I could be wrong but I believe the vent primarily provides air into the house sewer piping system as water is flowing. If the vent is clogged I would expect you might see a small water level lowering in the toilet p-trap, which is easily observable— or just some water movement in the bowl while water is flowing through the system. I’m not dead set against the vent blockage suggestion. I personally would just start carefully snaking things (vents and pipes) to eventually get to a solution.

The venting and almost all the piping is a direct line to the "swamp gas", the stink is stopped by the presence of water in the P trap of each fixture. The toilet has an internal P trap, the shower has one underneath the shower in the floor framing, the vanity has one under the sink.
Yes, the venting accelerates the ability of the piping to drain, so with clogged or insufficient venting the pipes won't drain as well.
But the OP saying that they are observing the smell in multiple locations is why I'm suspicious of the venting. If the venting is plugged then you'll likely get a build up of gas in the system which could show up in any or all locations.
But definitely snake each fixture as well. If you have access to the shower p trap open that up, too. I would take a hose on the roof and fill the vent pipe and see if it overflows.
There's a garden hose attachment you can buy that is rubber with a tiny slit at the end. This expands to the interior size of the pipe so water can't get back out and it forces a pretty strong flow down stream. Push that in as far as possible and turn on the hose. It's helpful to have an assistant in the bathroom listening, you might hear it break up some gunk and start flowing. If you have a clean out downstream open it up and see if any water is moving.
I'm sure this tool has a name but I only know them as a "donkey dong" ;-).
Good luck

[lthenderson]

I would take a hose on the roof and fill the vent pipe and see if it overflows.

One word of caution. I remodeled our master bathroom a decade or so ago and put in a flush mount medicine cabinet which required me to cut the vent pipe and move it alongside the cabinet. After I was done with the bathroom, I noticed many things not draining properly and sewer gas in various places of the house. In the process of diagnosing why, I discovered up in the attic that one joint of my vent pipe had evidently never been glued. My jostling of the vent pipe in the bathroom had caused that joint to fall loose and it rotated into the attic insulation, restricting it's venting capacity. I reattached the joint, gluing this time around, and everything went back to normal.

I shudder at the thought of the damage I would have caused trying to fill up the vent pipe from on top of the roof with a garden hose. I think I would make sure someone savvy was down below to quickly alert me if water started coming from places it shouldn't.

[FireOnTheMuffin]

Thank you all!  I'm going to give a bunch of this a try.  @lthenderson, indeed I am too scared to try and put water down the vents... I know there is a studer vent somewhere along the way inside a wall, too.  I'm afraid I'll fill the wall with water!

[ChpBstrd]

As others said, the gurgling reflects water filling up the pipes and pushing the remaining air up through the P-traps in your shower, sink, or toilet. This can occur even if the venting is done correctly and working properly, because the water level eventually blocks the vent as it rises.

So I don't think you have a vent problem. I think something fell down into the sewer during the remod (e.g. a screw or piece of wood) and caught a bunch of debris (e.g. toilet paper) and created a very slow drain situation. Then when you take a shower and dump 30-40 gallons down the line, the pipes start to fill up, eventually reaching a point where air is trapped between the water level and the P-trap and gets pushed up through the P-trap by the rising water level.

What happens if you leave the cold water in the shower and sink running for an hour? Will the tub eventually back up?

The eventual solution is to use a scope to find the issue or snake the drain with a power snake using a root cutting blade. Whatever it is it's downstream of the bathroom, which is why none of the upstream work helped. See if your house has a "cleanout" pipe with a cap that can be unscrewed. This might be in the basement or just outside the house. If not, the plumber will probably remove the toilet and scope/snake from there.

[Just Joe]

I'll throw this out there too. A sink uses a P-trap to keep a puddle of water in the elbow pipe to hold out the stink.

However just this week I read about people incorrectly creating an S-trap by putting two P-traps back to back (sequentially) that causes the puddle of water to be siphoned out of the first P-trap - and sewer gases to flow into the sink area uninhibited.

Don't know if this is your case. Don't take my word as the final word. Just a clue that you should read more about. I am not an expert.

[NaN]

Do you have a before/after picture of the tub to shower conversion? I don't think the vanity or toilet would have made any difference, but the plumbing on the shower (if modified extensively) could have been installed incorrectly.

Proper plumbing up to code should never gurgle. Common mistakes are inappropriate wet venting and use of Ys instead of sanitary Ts. I'm sure there are others.