Sewer odor smell

I just bought a home and prior to purchase, could smell a sewer odor outside. I was told the prior owner had replaced the sewer line. Off and on I can smell sewer odor in one bathroom (the bath closest to the outdoor sewer clean out valve thing). The sewer smell is strongest from two places: the bathrub drain and also an old gas wall heater. The wall heater is on the wall closest to the outside sewer clean out, a few feet from that outer wall.

This odor comes and goes. It's hard to find a pattern, but it seems to start outside and get into this particular bathroom. No other rooms have this problem.

I was told it might be a broken P trap in the bathtub and to keep it wet. That doesn't seem to solve it. I was then told that perhaps when the prior owner put in the new line, they didn't bury it deep enough and it allows gases to get into the house. I haven't called a plumber yet, but would like to know what my first approach should be about this. I'd hate to replace a P trap if that isn't the problem (it seems to be an outside problem). I've heard it's very expensive and difficult to fix a bathtub P trap. Is that true?
This odor is quite bad at times, and I'd like to get this stopped once and for all. Any suggestions? Should I start exploring the outside first? Thanks for any information or feedback on this - it's gotten to be a real problem.

neither one of the two suggestions you have described make sense. Sorry to tell you that.

Sooner or later you will know a lot more about drain plumbing, so I recommend sooner being better than later. Draw out a top view of what you have in your house, and post it here. The side view will come later, with questions and answers.

David

I'd check the crawl space (if you have one). There could be a broken pipe down there. After that I'd have the sewer line camera'd.

Start out with checking for a gas leak. Often those old gas heaters and it's gas line or valve can put off an odor that MAY resemble sewer gases. This might be the way to narrow down your search and be the most cost efficient.

Call your gas supplier and have them pressure test your sytem.

Thanks for the replies and feedback. About a top view drawing of the house, not sure why that's important, but I will say we cleaned out the vents that run down for any clogs like leaves or debris and they were perfectly fine. Also had the city come out and check to see if there was a blockage at the street, and there was none.

As far as the old gas heater being the culprit, not sure about that. The smell is also coming up from the bathtub drain, so if it was just the heater, I wouldn't smell it at the tub drain too, would I? However, I will check further into the gas heater leaking. As I recall, we had a gas guy here who ran a meter around the area and found nothing. So I kind of doubt that's it.

The main thing I've been told (not by professionals, just friends, etc) is that it's either the P trap or the line outside has some type of problem or wasn't installed properly by the prior owner. Could it be leaking out there into the soil, and then the odors are picked up and carried into that bathroom through whatever openings pick up the smell? Any further advice is greatly appreciated. I'm not rejecting any ideas, just trying to troubleshoot this problem, and it IS quite a huge problem which has been going on for months with no solution. Thanks!

The p-trap may not be located where it is supposed to be which means that more of the pipe (which could have accumulations of hair, oil, sludge, etc. on the walls) would be exposed to the air in between uses. The trap should be directly below the drain so there is less chance of trapping stuff above the water level. You could also have an accumulation on the stopper, depending on the type. If you have a lever operated stopper for the tub, take the screws out of the cover and carefully pull it out. Clean as required and reinstall. the exact procedure for that is somewhat dependent on the type of stopper.

p.s. we don't have a crawl space...it's a slab foundation. To my mind, having the sewer line camera'd is what I might end up doing (unfortunately, the most expensive option of all probably), because the odor was very strong outside the home when we bought it. Our home inspector didn't smell anything the day of the inspection and thus had no opinion about it. That's what's odd - the smell comes and goes. It might be dependent on the weather, like hotter days, or lots of rain. Not sure about that. But when a smell isn't always present, it makes it difficult to know where to start. But the outside smell was so strong when we first looked at the house that I still suspect the sewer line out there. If it hadn't been buried deep enough, would I be able to tell that from looking? Are there signs of that from the surface? Thanks for the info!

About the P trap in the tub, I guess we could clean it out, just to eliminate one area. It's a lever type. But again, since I've smelled it near the gas heater also, and outside the house, it seems a longshot that cleaning things out in the drain would do much good. However, I guess it wouldn't hurt to do everything possible before paying big $$$ .

doitmyself50 said:

p.s. we don't have a crawl space...it's a slab foundation. To my mind, having the sewer line camera'd is what I might end up doing (unfortunately, the most expensive option of all probably), because the odor was very strong outside the home when we bought it. Our home inspector didn't smell anything the day of the inspection and thus had no opinion about it. That's what's odd - the smell comes and goes. It might be dependent on the weather, like hotter days, or lots of rain. Not sure about that. But when a smell isn't always present, it makes it difficult to know where to start. But the outside smell was so strong when we first looked at the house that I still suspect the sewer line out there. If it hadn't been buried deep enough, would I be able to tell that from looking? Are there signs of that from the surface? Thanks for the info!

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It shouldn't be a matter of the sewer being not deep enough, it's a matter of having the proper grade and not being broken. If it's broken, it's possible that is where your smell is coming from. Either dig up the entire line to inspect or camera it.

If you decide to camera it I would do it from the farthest water closet, so the under slab drain can be inspected as well. Some rental yards have sewer cameras.

If you think it might be gas, try turning the gas off at the meter and see what happens.

Thanks for the further advice - just out of curiousity, if the P trap in the bathtub drain is involved, what's involved with fixing that? I've heard it's very expensive or requires tearing stuff out. Is that true? The tub is most likely original to the house, built in 1954. The tub wall shares the wall with a closet on the other side. Any ideas?

Where is the vent for the gas heater in relation to the sewer vent? If they are close together, you might be noticing it from there. Try removing the tub stopper and see if it is covered by hair, etc.

doitmyself50 said:

Thanks for the further advice - just out of curiousity, if the P trap in the bathtub drain is involved, what's involved with fixing that? I've heard it's very expensive or requires tearing stuff out. Is that true? The tub is most likely original to the house, built in 1954. The tub wall shares the wall with a closet on the other side. Any ideas?

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if you believe the p trap may be an issue, i'd cut out some of the drywall in the closet behind the tub drain and you may be able to see the trap or maybe not. replacing a tub p-trap is usually pretty difficult from the opening in the drywall. removing the tub is one way and tunneling from the outside is another. Jackhammering the floor in the closet may also work depending on which direction the drain goes.

It's also possible, but not likely, that with the right weather patterns, the smell could be coming from a neighbor.

is there NO P trap? It's entirely possible given your symptoms. Check that.

No offense meant, but I would like to say that your answers are sketchy and your questions are often too far ahead of the game. The time now is for fact-finding. Let's figure out what you have there. Let's inventory what you have.

Brent already mentioned that it is not a "not deep enough" problem, just as I did. He mentioned two other possible problems.

So far, we don't know for sure from your descriptions above if you have a septic tank or if you are on a city sewer, since you haven't said so clearly. This is important information for all to know, and for you to share. This is part of "getting the facts." After your thread has another 30 or 40 posts, the few facts that need to be known will be buried in bits and pieces here and there throughout the thread. Now would be a good time for you to describe what you have. What plumbing you have. How it is connected. The smell has to be coming from something that is not connected right and is letting sewer gases escape.

Also, how far away is the closest neighbor? Have you spoken to him about these smells to see if he has noticed it too?

David
.p.s. your other idea tossed out, about a "broken" P trap, may be an option, since your plumbing is buried in a slab, and that would leak water downwards where you wouldn't see it. To diagnose whether it is broken (cracked), you have to observe the water level in the P trap after putting some water down into it.

Further info: I'm on city sewer, and I had the city come out fairly soon after buying the house to check for a blockage at the street and they found none.
I'll check to see whether there's NO P trap at all, although a friend of mine who looked down into the drain probably would have noted if there had been none. He keeps advising me to keep the trap wet by running some water everyday in there, but that didn't help. And as I said, the smell also comes through from the old wall gas heater area too. The nearest neighbor next door has smelled the odor outside intermittently just as I have. I feel very strongly that something hasn't been hooked up right, and as you say, is allowing sewer gas odor to escape. Since the opinion seems to be that deeper burial of the pipe is not an issue. I'll cross that off my list of things to check for. The fact that the prior owner put in a new sewer line makes me suspicious that it either wasn't put in right, or there's a crack somewhere. Also, I had a gas guy out for another issue with the house and while he was here, I had him come outside with me to the cleanout valve thing that sticks up above ground (near the wall where this bathroom is) and I said, "Can you smell that?" And he goes, ' YEAH!" He was the one who suggested I call the city to check for a blockage at the street, which yielded nothing. But he certainly did smell it out there as I did. Right there at the clean out thing. It was on one of the "stinky" days when it's bad. We were OUTDOORS so it would seem that something about the line outside isn't right. That's not to say there isn't something further wrong with the P trap or heater or something, but it seems logical to think that if it can be smelled outside, if that's fixed, it can't get into the bathroom anymore. Hope I've answered more of the questions......no offense taken at all. I'm new at this as you can see! Thanks again for your feedback, it is helping a lot.

dig it up between the clean out and the house, all the way to the pipe. tell us what you find. have you cut open the drywall behind the tub. Open the clean out and look in and tell us what you see, water or not? how deep is the sewer? Tried turning off the gas?

2 problems, compounding. That may be what you have. It's a hunch. Maybe, for example, a tub with no P trap, and a crack in the outside drain to the sewer.

david

About the possibility that the tub has no P trap, a friend of mine looked in there who's fairly experienced with plumbing and never mentioned that it didn't have a trap. So it probably does. However, if it doesn't have one at all, how would that happen? The tub is probably the same one that's been here since the 50's, and if it never had a P trap, I would think several owners would have been bothered by smells and other problems. Under what circumstances would a tub have no P trap? (i.e. never installed in the first place? Does that happen?)

About the possibility of a crack in the line outside, the odd thing is that the smell comes and goes. It seems worse in hot weather, although I have smelled it in colder weather too. If there were a crack, I'd think it would be there all the time. So, that's another puzzle in all this. It makes it difficult to show a plumber the problem when there's no smell on certain days.

I had another idea, which is probably not valid, but the prior owner replaced the other pipe as I recall because it had broken. Could sewage have spilled out into the ground at that time and remained there to cause odors?

As far as digging up the ground from the clean out all the way down the line, I'm hoping to avoid something that huge. That would be the last resort. I'd
opt for putting a camera thru first. I'm sure that's a big expense too, but I'm running out of simple choices. Thanks again!

when a seal is broken, the device is not broken, just the hygienic seal that the device made. When you open a glass jar of spaghetti sauce, the pop is when the seal breaks. So far so good; this may sound like baby talk but bear with me. A P trap seals, in a different way. If something like a blocked vent (which is downstream of the P trap) causes the P trap to "break its seal", that doesn't mean the P trap is broken. The seal it makes is broken.

My first request was to ask you to draw it all out. Reading the above, can you see why? A vent mght be blocked. I'd like to know what you have there. Someone telling you about a broken P trap seal is a distinct possibility and far more likely than someone telling you about a broken P trap.

In the previous post and another one almost right before, you mentioned that a friend didn't spot there being no P trap. What I'd rather see is "how do I check for myself?" Then, you can progress to the next step, checking whether its seal is intact. Easy as pie. No need to quote a friend and discuss whether it is likely or improbable.

Recent threads have dealt with how to check for whether a P trap is even there or not. One started by molo, I believe. Recent threads have mentioned cases where there was no P trap to begin with. A post by frenchie, I believe. It happens. And some people would say it happens more often when the drain plumbing goes under a slab. Nobody can see from underneath whether there are P traps, later, and so no-one can ring alarm bells later.

As for a possible crack ouside causing a continuous problem, the answer is no.

David

doitmyself50 said:

About the possibility that the tub has no P trap .... it probably does.
....
About the possibility of a crack in the line outside, the odd thing is that the smell comes and goes. .... If there were a crack, I'd think it would be there all the time. ....

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here is another thread about an intermittent smell, caused by the lack of any P trap. The smell is off and on.

Click here: https://terrylove.com/forums/showthread.php?p=94293#post94293

david