We’ve been noticing an odor in one of our bathrooms. Some data points:
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[li]The bathroom is in a single-story house, typical US rancher style house. It is on the exterior wall (i.e. bathroom has a window).[/li][li]The bathroom has, in order: window, toilet, bathtub, 2 sinks side by side.[/li][li]The odor seems to be strongest near the toilet, but the bathtub drain is close to there as well.[/li][li]The odor is closer to a sewer smell than fresh poop smell, but hard to tell.[/li][li]The odor is intermittent, sometimes very bad and sometimes barely noticeable. We cannot find any pattern related to toilet use, tub/shower use, etc.[/li][li]The toilet, tub and 1 sink are normally used daily. [/li][li]We already tried running the water on the 2nd sink periodically, to make sure the trap doesn’t dry out. It seemed to reduce but not eliminate the odor.[/li][li]There is another bathroom right next to this bathroom (facing the same exterior wall). There is no odor there.[/li][li]None of the drains seem to be clogged.[/li][li]There is a sewer roof vent nearby, I think it’s in the wall between the 2 bathrooms. Haven’t tried to clean it out yet.[/li][li]Yesterday we returned from a 3-day vacation, and there was no odor in the bathroom. But the odor returned this morning. [/li][li]We already called a plumber a few weeks back, he said “I don’t smell anything, don’t know what to do” and went away.[/li][/ul]
Are there any DIY diagnostics or possible fixes we could do? If we call the plumber again, what should I tell him to look for?
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[li]The toilet, tub and 1 sink are normally used daily.[/li][li]We already tried running the water on the 2nd sink periodically, to make sure the trap doesn’t dry out. It seemed to reduce but not eliminate the odor.[/li][/ul]
Every fixture has a trap. A trap is designed to create a water barrier to the sewer so sewer gasses don’t migrate into the structure. For them to work water has to be in them; they have to be primed. A bathroom fixture that isn’t used regularly wil have the water in the trap evaporate. (goddamn you mother nature) They “lose their prime.”
If that’s the case, the solution is to run water in EVERY appliance for 15 seconds every month. I’ve seen it many times. This includes floor drains. EVERY outlet
I would try cleaning the sink traps first. Especially sink #2, if you think it got better after water…? Or put bio-angents or bleach in them if you aren’t up to it. They can get pretty foul and full of some thick ugly smelling goop and still drain. Tub drains (depending) are often harder to get access to, put try to get something in them as well. I’ve had the best luck just taking apart the traps and cleaning them.
Also, have you looked in the crawlspace beneath this bathroom to look for leakage there? How old is the house? If you replace the wax ring on the toilet, check the flange and soil stack for condition and make certain the pipe comes up far enough to meet and seal properly with the ring and toilet base. (been there done that, turns out the inspector when my house was built must have been [del]bribed[/del] blind)
Yes, that’s why we have been running the water on the sink #2 periodically (every week when I clean the bathroom). That reduced the odor, but not eliminate it.
Thanks, I just went and did that, and indeed one of the sink traps had some foul-smelling sludge in it. Hard to tell if that was the cause, but we’ll definitely monitor the situation and see if it solves or at least improves the situation.
That’s a possibility. When we replaced the toilet a few years ago, the plumber didn’t install the wax ring properly and it was leaking. We hired another plumber to re-install the toilet (new wax ring) and there is no visible leak since. But if this seal has gone bad again, wouldn’t water be leaking out of it, in addition to sewer gas escaping from the gap?
Then again, the second plumber did say he had difficult with it because the pipe isn’t flush with the floor.
Unfortunately the house is on a slab, no crawlspace beneath. I believe the toilet drain and the bathtub drain (including the trap) are embedded in the slab. The house is about 30 years old.
Trap problem, e.g., dried out or clogged.
Wax ring.
Poor pipe fitting. The connections from a sink trap to the wall pipe can be surprisingly shaky.
Clogged air vent. (Sewer gas can mix a small bit when a drain goes glug-glug.)
The vent pipe may be clogged. It sticks up through through the roof over the bathroom. It does not have a cap on it and is about 2" in diameter. Get a garden hose and go in from the top on high pressure. If the vent pipe is clogged it should break the clog. It should not flood anything inside as it is just a vent. Might make your drains work faster.
Thanks. I was just up on the roof inspecting the vent. Tried pouring water into it, and it flowed cleanly without backing up. I stuck an auger into it and it seemed to extend all the way to the bend at floor level.
I’ll inspect the pipe between the sink trap and the wall, thanks!
As for the bathtub drain (presumably embedded in the slab), would a cheap USB borescope work for inspecting the drain?
It seems after those steps, the remaining options are (1) lifting the toilet to inspect and possibly replace the wax ring, and (2) pulling the bath tub out and fixing the bathtub drain?
List is where I would start also. If your stool flange is somehow damaged or below the floor level you may need that repaired, ask for an old timer of a plumber. Seriously! an old timer will have seen more types of failures and will have a wider range of repair options.
As an old time plumber myself, I knew of a stool flange repair that none of my younger colleagues had heard of.
In the case of plastic underground plumbing metal flanges what are not made of stainless steel tends to rust away, plastic flanges are prone to breakage especially when they are not properly anchored.
Depending on the area you are in, the building contractor and the plumber the original installation may have a relatively large gap between the flange and the concrete floor. the larger the gap the more difficult it is to get a good anchor.
An old timer will have developed some plan to address either condition.
In a 30 year old house it is unlikely that you have Cast Iron drainage, non the less the repairs to broken CI stool flanges is very similar to Plastic.
I had the same problem that bedeviled me for weeks. Turns out, birds built a nest in the exhaust, then abandoned the nest and the eggs began to rot. There was also a dead bird in there.
Get up on the step ladder and sniff around the exhaust vent in the bathroom.
I ended up calling the ventilation guys and they came out with a powerful vac system and compressed air that blew the nest and carrion outside. They then had to spray industrial disinfectant to ensure it no longer stunk.
These great suggestions (which I will remember!) also reminded me to mention that if you can differentiate the smells, sewer smell is kinda “shitty”, often “warm” and tends to rise, whilst stagnant traps are often “rotten eggs” “foulish” and “cold”…I know, not very good descriptors.
Rats can also die in really teeny obscure places, but they smell worse then all the others put together, very peculiar ugly smell.
I agree with suggestion about broken toilet ring, even though its slab, it will probably be an unsealed cut through the concrete, and a wobbly toilet will open a gap for air to pass. Or a poorly mounted one. We use the extra thick rings often here, when replacing toilets. (10 bathrooms, old house)
My daughters toilet seal was hard to keep in good order. The last time i found at the home do it yourself chain store that isn’t very high …
A Rubber seal to replace the wax seal that didn’t last.
Our toilet would get limed up a lot, and wasn’t flushing with enough force, and so we had intermittent smell problems. We flushed it all through with Lime-Away. I actually had to get a disposable douche bag, fill it with Lime-Away, and squeeze it up the small hole in the bowl to clear out the flush holes in the top of the bowl. Worked like a charm, though. After de-liming the toilet, the smell went away. We had to repeat this process about once a year to prevent it happening again.
I have double sinks in my kitchen and use one to wash my dishes ,my dish rack is on the other sink. I have to run hot water in the sink with the dish rack or it’ll get stinky from hydrogen sulfide .
ah, a slab, well, that changes things. I mentioned crawlspace because when my bathroom “went bad”, it was because the original builder (well, the person he hired to plumb the house) cut a 10 inch section of the floor joist out to run the stack for the toilet and didn’t reinforce and support it. After 30ish years I had to remodel the entire bathroom and repair the floor and the sewer pipe, because I had almost 3 inches of drop from the door to the toilet (about 5 feet) and a broken pipe flange. So anything that interferes with the seating and sealing of the toilet on the ring and top of the pipe can (will?) result in problems.
I just wish I had something better to offer you for advice, after having said all that.
A slow drain with multiple fixtures can cause this same problem, it almost backs up. It has enough back up to force some smelly pipe goop past the trap but not enough to be visible. You may need to run a small snake through the fixtures. I have this problem about once a year and the smell is the first thing that tips me off.