Shower causing bad smell

September 28, 2008 9:36 AM

An extremely foul smell (not a shit smell -- I can't place it) has been starting up in my bathroom a short time after the shower is turned on. It doesn't seem to be the water itself that smells, but I can't tell where the smell comes from. When the shower is off, the smell eventually clears and doesn't return until the shower is turned on again. Any idea what could be going on?
posted by Cucurbit to home & garden (21 comments total)

Nasty gunk in your drain?
posted by emd3737 at 9:40 AM on September 28, 2008

We had a problem with our (electric) shower a while ago, and when it was turned on there would be a smell similar to lead solder. There was also a small-ish amount of white smoke, but it wasn't obvious if the water temperature was high, as it was obscured by steam. In the week or so before the smell/smoke appeared it had been pretty unstable water-temperature-wise.
I'm not sure what exactly the problem was in the end, but the electrician fixed it pretty easily - though it's probably not a great idea to use the shower in the meantime if your problem is electrical like this.
posted by pocketfluff at 9:50 AM on September 28, 2008

Yea, like emd says, it could be stuff growing in your drain and when the water hits the drain, it forces the gases up into the room. I've had that happen with a kitchen drain.

Does it smell like rotten eggs? I know you say it doesn't smell like it's coming from the water but sometimes this smell can develop in the hot water heater and it's really obvious when the water is turned on. But then it would smell like that at every hot water tap, not just the shower.
posted by cabingirl at 10:12 AM on September 28, 2008

emd3737: The possibility of it being gunk in the drain occurred to me, but then why wouldn't I smell it all the time instead of just when I turn the shower on?

pocketfluff: My shower isn't electric.
posted by Cucurbit at 10:13 AM on September 28, 2008

What's the smell? Hydrogen sulfide, or rotten eggs? If so, then it's probably
from your water, and probably from your hot water. Check the odor of the
water from your kitchen sink hand sprayer. If the hot water stinks but the
cold water does not, then it could be sulfates in your water reacting with
the magnesium sacrificial anode of your electric water heater.

Do you have galvanized pipes or copper pipes or plastic pipes? If you have
metal pipes, hydrogen sulfide stinky water becomes unstinky after it sits in the
pipes or a little while, you when you test your hot water for odor, you have to
let it run and get good and hot.

Does the drain go glug, glug glug or does it drain easily?
If glug glug glug, then foul odor could be coming from decaying junk in pipes, and
your vent is clogged. Snake the drain from the shower stall, and snake
the vent from the roof.

Does the foul smell take days to go away, or just hours? If days, then the
pan might be leaking, feeding mold and decay in your subfloor. Check under
the house for wetness underneath the shower.

I'm tracking a stink today myself. We tested the gasoline generator extensively
a day or two ago, and now there is a decidedly organic stink emanating from
the machinery. Those poor little mice...
posted by the Real Dan at 10:13 AM on September 28, 2008 [3 favorites]

cabingirl: Ah, I see. I'll definitely check out the drain, then. I don't think the smell is like rotten eggs, and I haven't smelled it at any other tap.
posted by Cucurbit at 10:22 AM on September 28, 2008

not to gross you out, but ... do you share the shower with anybody? If somebody is peeing the shower regularly, it can lead to a persistent odor.
posted by pjenks at 10:27 AM on September 28, 2008

Yeah, it's because as water flows down your drain, it displaces the air that is sitting there in the drain. If there is something foul smelling in the drain, that air is going to be smelly.

A thick drain cleaner like Drano Gel can often clear whatever is causing this, even if it isnt obstructing the drain. Often it's a plug of hair and soap scum that traps other stuff and is a place where bacteria can grow.
posted by ikkyu2 at 10:47 AM on September 28, 2008

The drain. Simple solution - pour one cup of white vinegar into the drain followed by one quarter cup of regular table salt. Let sit for approximately 2 hours. Boil hot water and using a spouted vessel pour into the drain to wash away all the gunk that's causing your stank problem. If this does not clear up the problem - use 1/2 cup chlorine directly into drain. Let sit. Follow with approximate 1 gallon hot water. That'll flush any residue left.
posted by watercarrier at 10:51 AM on September 28, 2008 [2 favorites]

One thought is that you have a second drain in your bathroom (say, your sink) that is venting sewer gas (smells nasty but not always distinctly poopy) back up into your house. The reason this would happen only when the shower is running is that usually you have a bit of standing water in your drain that acts as a barrier between the sewer and your house (it's the reason you have that J-shaped "trap" below each drain). The draining of the shower creates suction on all the pipes nearby that empties them, causing sewer gas to be able to escape.

Normally this should not happen because drains should be vented (those are the pipe outlets you can see on most rooftops). However if your plumbing is older your house won't have this. Also sometimes an animal crawls into your vent stack and dies, causing your plumbing not to vent properly.

One way to test my theory is to plug your sink before the shower, and see if the smell goes away. Alternatively, set the sink tap to run a trickle of water, which will prevent the suction issue I described above.
posted by drmarcj at 10:57 AM on September 28, 2008

Thanks for the advice, all! So when I get home, I will first test drmarcj's theory, and if the smell still accumulates I'll pour Drano down the drain and see if that does the trick.

If I can't eliminate the smell over the next couple days, should I be worried about taking a shower during that time, or is it likely that the concentrations of hydrogen sulfide or sewer gas or whatever wouldn't be enough to be harmful?
posted by Cucurbit at 11:09 AM on September 28, 2008

Cucurbit - don't use the Drano before you try the vinegar and salt solution. It's much LESS toxic to the environment. All of those chemicals go into the water system. And don't ever use Drano and chlorox either together or one after the other. It's highly combustible.
posted by watercarrier at 11:15 AM on September 28, 2008

watercarrier: OK, I'll try that method first.
posted by Cucurbit at 11:20 AM on September 28, 2008

Are you on a well? My parents had the exact same thing and they had to have their well treated. The guy poured a very small amount of a clorox type solution into their well and it went away. They would repeat about 3 times a year. You could smell it in the shower so well because it was a large amount of heated water. Made it more noticeable.
posted by pearlybob at 11:20 AM on September 28, 2008

Drano is just sodium hydroxide, sodium hypochlorite (the basic salt of bleach), a gel forming detergent compound, and water. When it gets into the sewer it quickly turns into water and salt plus a little detergent. It's not going to be any worse for the environment than watercarrier's method, nor doing a load of laundry.
posted by ikkyu2 at 12:24 PM on September 28, 2008 [2 favorites]

If you still smell it after you clean the drain, you may want to start the shower with a bucket in hand, get yourself several cups of water in the bucket, take the bucket out of the bathroom, and then get your face down to the bucket and smell. That'll tell you if it's the water itself, or if you should stick on the drain track. If you have a handheld-type shower with a plastic or metal hose, you may want to remove/clean and replace that, if the smell is definitely the water.

If the smell IS the water, try hot-only and cold-only. If it's hot-only, it could be the water heater.

Also, if you have a leak in your shower liner or tile, you may have something growing behind/under that doesn't really carry the stench very far until it gets wet or damp (or you stand over it). If you don't have very strong light in the shower, get a strong flashlight and examine your grout and seals.

If you have a shower/bath, you may have something in the stretch of plumbing between the drain and your overflow valve. You can use a squirt bottle to squirt your vinegar solution up into there as well.

At certain times of the year, our city water smells awful, but it smells awful like public city pool and I know it's the algae treatments in the reservoirs that do it. If it's a chlorine-type smell, that may be your deal too. I can rarely smell it at the other taps, as the volume is too low, but on a bad day I'll get it at the kitchen sink too.
posted by Lyn Never at 1:14 PM on September 28, 2008 [1 favorite]

We have a similar problem in our master bathroom, which has a sink, shower, and very rarely used two person spa tub.

I've been trying to figure out whether or not there's a correlation between water usage and the occasions when the problem surfaces. It doesn't happen often, but when it does it's nasty.

We've tried Drano, and we've run all manner of cleaning cycles on the spa tub.

I'm ready to try what watercarrier suggested and assuming we'll have to ultimately go to the chlorine treatment but am wondering if it's still a good idea if we're on a septic system?

This problem only surfaces in the master bath in our three bathroom home. Everything drains just fine all over the rest of the house, and this is not a water odor.

It is not beyond the realm of possibility that our vent is clogged on the outside. It's right above this bathroom but on a very high, severely pitched roof and I can't get to it with my 24' ladder.
posted by imjustsaying at 3:44 PM on September 28, 2008

Had exactly this in my bathroom sink. It only came on when I turned on the water because it stirred up whatever was in the drain. I poured in some gel drain cleaner/clog remover and it went away. Has not returned since.
posted by Kickstart70 at 4:01 PM on September 28, 2008

For what it's worth, an occasional stock-pot full of boiling water and vinegar keeps the dran clear and happy, and is pretty innocuous if you've got a septic tank.

I dye yarn at home and pouring off the water/vinegar is part of the process, and I haven't had slow drains in ages.

Just be careful carrying the pot from the stove-top to the shower. Bad time to trip on a cat.
posted by Lou Stuells at 5:18 PM on September 28, 2008 [1 favorite]

This happens at my mother's house - a few seconds of water running down it and you get this nasty drain stink. I would dump a bunch of Drano down the, y'know, drain, and see what happens! Drano is great fun.
posted by turgid dahlia at 5:23 PM on September 28, 2008

If you have a drain that's rarely used (bath, shower, floor drain, etc), it's possible that the p-trap has dried out enough to allow sewer gas to come up through it.

Try pouring a few cups of plain water into every drain hole you have to top up all the p-trap/j-bends.

I had exactly this problem in a downstairs bathroom a week or so ago; the toilet and sink were used frequently, but the shower never so. It fed into the floor drain, which was letting sewer gas in. Pouring about a litre of water into the floor drain (or running the shower every now and then) filled the p-trap up enough to stop the stench.

Note that the sewer gas doesn't have to be coming up through the same drain that the water's going down; displacement can force the gas up elsewhere, and it's stinky enough that it almost doesn't matter where it's coming from.
posted by 5MeoCMP at 5:47 PM on September 28, 2008