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View Full Version : Methane Odor in Basement Bathroom



artistsnature
10-22-2008, 06:28 PM
I'm a single mom in Jersey and I try to do all my own work. The house I bought a year ago had A LOT of plumbing "issues". The septic failed, the well was filled with bacteria, the well tank inside was filled with silt, mud came out the faucets. All that was "fixed" before I moved in. Originally I thought the smell in the basement was due to a propane leak - which was true, and I replaced both the propane fitting on the dryer and the propane oven above. That helped, but the smell continued. I tore down the moldy ceiling in the basement bathroom to fix a loose, dripping fitting in the trap of the shower above. I replaced the sink and toilet in the basement bathroom. I installed a trap missing from the stand pipe of the washer. The downstairs shower isn't functional - when I started to refinish it, I saw that the handles are six inches off center, and I haven't tackled that yet. So I periodically pour water down the shower drain to make sure the trap - if it exists, which I doubt because the whole bathroom was just slapped together - stays wet. I even installed a bathroom vent, but it's no match for the smell, which gets much worse when I run the dishwasher or shower.

I thought the problem was the vent stack - it's a steep pitched A-frame roof, and the stack is below the top bathroom, and only sticks up 6 inches. There's only one 1.5" stack in the entire 3 bathroom house, which seems inadequate. It looks like the upstairs 1/2 bath is unvented (that sink is also not working, because it's rotted through and I just shut off the supply). The methane odor used to consume the back yard, but I extended the stack two feet and that helped outside.

The gutters of this house hadn't been cleaned or maintained in decades, which caused leaking in the basement. I fixed all that. But I wonder whether the vent stack, which was not capped, could be clogged too? The leaves were so composted in the gutters that they turned into the richest soil I've ever seen - could that be in the stack too? I don't have any drainage problems in the appliances, so I doubt that the vent stack is clogged, and I also don't hear any gurgling.

When I started to re-do the basement shower, I did not replace the pan - even though the septic had backed up in there decades ago and the shower was full of crap. Should I pry off the pan to see if there's a trap? Should I run a hose down the vent stack to see if it's clogged? Should I do a peppermint oil test? Do I need to install an extra vent stack? I really don't know what I'm doing, although I muddle through and figure a lot out. But I can't afford a plumber - can you help?

THANKS!
Caryn

xroad
10-22-2008, 11:11 PM
I tend to like to rip out old plumbings and replace with new, Get cheap stuff if necessary but it has to be new. Old stuff just not worth the time to struggle with.

If you don't have the time to rip into the pan to see if there is a trap, just seal it and wait for a few days to see if the smell discipates. Once you rip it out, you are in for that project until it is done. I am sure you have other more pressing jobs. Find a cap, an old pie pan or something to cover the drain with a bead of caulking for seal.

Looks like you have some major issues. Take care of the health risk issues first. Stabilize situation and decide what to tackle first. If the basement is always wet, from the septic tank? That is dangerous to your family's health.

Good luck.

khayes
10-23-2008, 05:09 AM
We had a similar problem in a house years back - would get the odor in the basement after it rained or after a large amount of water usage, ie. running the clothes washer (which was also in the basement). It turned out to be a section of crushed field line going to my septic tank. Once I had that replaced, the problem went away. Good luck.

artistsnature
10-24-2008, 06:55 AM
We had a similar problem in a house years back - would get the odor in the basement after it rained or after a large amount of water usage, ie. running the clothes washer (which was also in the basement). It turned out to be a section of crushed field line going to my septic tank. Once I had that replaced, the problem went away. Good luck.

Interesting thought - although the entire septic system was replaced, from the output pipe to the tank to the field, so unless the problem is under the basement shower, I assume the lines are ok.

Does anyone think that I need to install an additional vent stack? Is this a job a novice can take on? The top-most bathroom is covered ship to stern in tongue and grove knotty pine, so I'd hate to have to rip it out. But if venting that bathroom would make the odor in the basement bathroom go away, I'll do it. I just hate to start that project if it doesn't fix the problem. (BTW, I had a plumber out and he said it would not fix the problem. He said it was the missing stand pipe trap, which I installed, and the odor did not change).

Cass
10-24-2008, 07:21 AM
go buy a rubber stopper/cover and place it over the shower drain and see if it changes anything

artistsnature
10-24-2008, 07:49 AM
go buy a rubber stopper/cover and place it over the shower drain and see if it changes anything

Yeah, already tried that. No improvement.

patrick88
10-24-2008, 07:56 AM
I would try a smoke test. The peppermint test can be a real pain. The peppermint gets in your nose and you smell it every place.
You could have a cracked pipe some place under the shower. I would not bother lifting the pan until you know you really need to.

Southern Man
10-24-2008, 08:49 AM
Before you do anything call your propane supplier and have him test all the gas lines for leaks. He'll probably do it for free. Once you get that eliminated as the problem then you can do a smoke test for the septic system. Call up a local tank cleaner and have your tank pumped and cleaned, and the house sewer smoke tested.

artistsnature
10-24-2008, 09:08 AM
Before you do anything call your propane supplier and have him test all the gas lines for leaks. He'll probably do it for free. Once you get that eliminated as the problem then you can do a smoke test for the septic system. Call up a local tank cleaner and have your tank pumped and cleaned, and the house sewer smoke tested.

I have been considering a smoke test, although I've read that they can be screwed up (not enough pressure, etc.). Is this something I can try myself - rent a machine somewhere - or do I need to leave this one to the pros?

BTW, the septic was new less than a year ago - it had evidently not been pumped for a very long time, because not only had it backed up into the downstairs shower, but during the test they found the soil around the tank (overflowing) completely saturated for six feet down. Between the septic backup and the silt from the well, I'm wondering whether there could be a clog somewhere......

Southern Man
10-24-2008, 01:22 PM
I have been considering a smoke test, although I've read that they can be screwed up (not enough pressure, etc.). Is this something I can try myself - rent a machine somewhere - or do I need to leave this one to the pros?

BTW, the septic was new less than a year ago - it had evidently not been pumped for a very long time, because not only had it backed up into the downstairs shower, but during the test they found the soil around the tank (overflowing) completely saturated for six feet down. Between the septic backup and the silt from the well, I'm wondering whether there could be a clog somewhere......

I've never seen the smoke tablets on sale at any DIY place. That test is done by placing the tablets in a low spot in the system and having the smoke rise up through the house drains. It should all exit the roof vents and if not you'll know where leaks are. Unless you know at least the rudiments of this and how the plumbing is laid out you should leave this to the pros. And this is coming from someone who is loathe to call in a pro.

Assuming that you don't have a propane link (see my last response, please) and your septic system is OK that the problem is likely to be all the spilled sewage in the yard.

Is your septic system operating properly? If the system was never pumped out for a long time then it backed up by clogging the drain field below the tank. That's a very common occurrence for systems that aren't maintained and once it occurs then the drain field has to be replaced. Was this done? If not then the system will back up again and that's were your odor is coming from.

The other possibility is due to septic spillage in the soil around the tank as you described. If it's close to the house then it may have saturated the building footing drain and then in the gravel layer below the floor slab. In older homes the basement sump is part of this system. If this is the case then you'll have to isolate the sump. You might be able to vent the slab and/or walls using a fan driven system similar to what is used for radon removal.

artistsnature
10-24-2008, 01:34 PM
I do have propane tanks, but they were replaced 6 months ago, when the propane leaks were fixed. Only the dryer and oven are on propane. Is it safe to do a smoke test with propane in the house?

The septic system is brand new - tank, field and all. When they were replaced, so was all the soil, so there's no odor in the yard itself. That's why I can't figure out where the smell is coming from in the basement bathroom. Is it worth it to get a gas detector at a DIY place? Of course, the septic guy says call a plumber, and the plumber says call the septic guy!

So if the smoke test starts at the lowest point, the tablet would be put in the shower drain? And isn't there a machine that blows the smoke through the system?

Thanks for all your help!

Southern Man
10-24-2008, 05:55 PM
Is there water in all your traps? Do you have a floor drain that is never used and the water evaporated out? Do you have a sump that collects from the footing and is that where the odor is coming from? Check all the obvious before you worry about smoke testing.

I've only done smoke tests on public sewers. We seal off one pipe in a manhole with a rubber plug and hang a smoke candle in the manhole, and use an explosion proof fan set on the back of a truck and connected to the manhole with a 2' diameter expandable hose (like a huge dryer hose) to put it under a slight pressure and force smoke up the other pipe. We then look at the connected homes to make sure all the smoke is going out the roof vents, and check with the occupants that there's no smoke in the homes.

I suppose with an individual house on septic you would open an access hatch on the tank and do the same thing. But the problem is that there is water in the tank within 2-4" of the top. You'd have to figure a way to plug the effluent end during the test, and making sure that the inlet end is not underwater. Then you have to have a fan small enough but powerful enough to put a slight pressure on the tank, and for it not to spark the combustible gas that is likely to be in the tank. Boom!

Maybe you could rent an explosion proof fan and the expandable hose, but that's going to be huge and expensive. Otherwise the only fan that I think would be safe enough would be an inline fan that connects to a 4" line like one used for radon remediation. Those can be bought for about $100. You can get a long length of dryer hose, like 20', and set the fan safely away from the tank and make sure its blowing the right way (towards the tank).

By the time you do all this you'd have spent about two days and $200 or more, so it's probably cheaper to call a pro who already has the equipment.

Redwood
10-24-2008, 07:14 PM
Maybe just call a pro?:cool:

Southern Man
10-25-2008, 05:02 AM
Ca-ching! :D

Redwood
10-25-2008, 05:49 AM
Somehow tossing M-80's into the septic tank doesn't seem like the way to go... I usually plug the septic tank during a smoke test and I also do not bring the generator inside the house.
Just a few thoughts on the subject that may make it worth the money.

artistsnature
10-25-2008, 08:21 AM
Is there water in all your traps? Do you have a floor drain that is never used and the water evaporated out? Do you have a sump that collects from the footing and is that where the odor is coming from? Check all the obvious before you worry about smoke testing.

Ok you guys, now that you've put the fear of God into me about smoke tests, I'm just about ready to take out a second mortgage and call a pro! I do have a floor drain issue, which I don't think is related, but you be the judge:

There is no sump pump and the traps are all wet. There is a floor drain in the utility room on the other side of the basement from the bathroom, and there is no smell from it. Not only was it dry, but when I pried off the top and shown a light, it appears that there's a hole in the bottom of it, which then leads to another gravel pit a few feet below. This drain is right below the well tank outlet, but really does not get used, as far as I can tell. Could this effect the smell in the basement bathroom?

Here's another question: if the drains are all working, wouldn't that indicate that the vent stack, however small, is working? In that case, wouldn't a smoke test be useless?

So if it's not the vent stack and it's not the traps, WHY THE HECK DOES MY BATHROOM STINK?????

Redwood
10-25-2008, 08:44 AM
My guess that more than likely its funk growing in the shower pan.
If the other common sources have been checked... Dry traps and leaking wax rings then proceed to the smoke test... It will uncover the dwv system leak if there is one. The smoke will give a visable indicator of any leak present.

artistsnature
10-25-2008, 09:19 AM
My guess that more than likely its funk growing in the shower pan.
If the other common sources have been checked... Dry traps and leaking wax rings then proceed to the smoke test... It will uncover the dwv system leak if there is one. The smoke will give a visable indicator of any leak present.

But if it's funk growing in the shower pan, why does it only stink when I run the dishwasher or the upstairs shower?

Redwood
10-25-2008, 05:27 PM
Hmmm Smoke Test!

Cass
10-26-2008, 05:28 AM
But if it's funk growing in the shower pan, why does it only stink when I run the dishwasher or the upstairs shower?


When you run water there is air movement through your DWV system and it is finding its way out somewhere where you can smell it instead of through the roof vents. This is why a smoke test may find the problem.

I had a friend who had a similar problem and we smoke tested and never found anything.

His odor would come and go different times of the year mainly spring and fall.

Redwood
10-26-2008, 08:22 AM
Basically in a smoke test, the openings in the system are all plugged. The line out to the sewer or, septic is plugged, the vents are all plugged etc. then the last opening I usually use a roof vent the testing apparatus is set up. I make sure all doors windows etc. are closed up then the smoke generator is used to pressurize the system with smoke. people wander around in the building and look for where the smoke comes from and the leak is found. Depending on the severity of the leak(s) we either stop the test immediately or continue to find additional leaks. It depend on the volume of smoke entering the building.

Bear in mind this test is only used after checking everything that we can see and all obvious leaks are repaired.

artistsnature
10-26-2008, 07:45 PM
Basically in a smoke test, the openings in the system are all plugged. The line out to the sewer or, septic is plugged, the vents are all plugged etc. then the last opening I usually use a roof vent the testing apparatus is set up. I make sure all doors windows etc. are closed up then the smoke generator is used to pressurize the system with smoke. people wander around in the building and look for where the smoke comes from and the leak is found. Depending on the severity of the leak(s) we either stop the test immediately or continue to find additional leaks. It depend on the volume of smoke entering the building.

Bear in mind this test is only used after checking everything that we can see and all obvious leaks are repaired.

OK, so in order to make sure all the bases are covered: is it possible that there is either a partial blockage in the basement shower, or a missing trap, that could cause this smell - and do I have to rip up the shower pan and check before I do a smoke test?

Redwood
10-26-2008, 07:55 PM
No but you should be able to see if there is standing water down in the shower drain. This woukl indicate the presence of a trap.

artistsnature
10-26-2008, 08:34 PM
No but you should be able to see if there is standing water down in the shower drain. This woukl indicate the presence of a trap.

Duh! Now I really feel like an idiot! I looked and there is indeed water in the shower trap!

I don't think anyone ever answered: Could the 1.5 inch vent stack below the top-most fixtures be inadequate for the 3 bathroom house? Would that cause the air to back up through the basement drain? Could I just tie an additional vent stack to the top floor sink?

Redwood
10-26-2008, 09:54 PM
If there is a backup then yes the drain water coming up in the shower could smell.

Under some codes the vent would be adequate... Some want full size out through the roof. in anycase it's probably not a problem. I don't know what code you follow as your local code.

Southern Man
10-27-2008, 05:40 AM
Somehow tossing M-80's into the septic tank doesn't seem like the way to go... ....

Somehow I don't see these having the same effect. :rolleyes:

http://testproducts.com/safecart/images/S105.jpg http://testproducts.com/safecart/product_info.php/cPath/91/products_id/165

Southern Man
10-27-2008, 06:08 AM
Is there water in all your traps? Do you have a floor drain that is never used and the water evaporated out? Do you have a sump that collects from the footing and is that where the odor is coming from? Check all the obvious before you worry about smoke testing.

Ok you guys, now that you've put the fear of God into me about smoke tests, I'm just about ready to take out a second mortgage and call a pro! I do have a floor drain issue, which I don't think is related, but you be the judge:

There is no sump pump and the traps are all wet. There is a floor drain in the utility room on the other side of the basement from the bathroom, and there is no smell from it. Not only was it dry, but when I pried off the top and shown a light, it appears that there's a hole in the bottom of it, which then leads to another gravel pit a few feet below. This drain is right below the well tank outlet, but really does not get used, as far as I can tell. Could this effect the smell in the basement bathroom?

Here's another question: if the drains are all working, wouldn't that indicate that the vent stack, however small, is working? In that case, wouldn't a smoke test be useless?

So if it's not the vent stack and it's not the traps, WHY THE HECK DOES MY BATHROOM STINK?????

I'm a little concerned about the vent size and location (below the highest bathroom) but if the stink occurs when you're running only the dishwasher or shower upstairs then I don't see how that could be the problem. If it was then the stink would occur when other units were draining.

Is there a possibility that the dishwasher and shower are connected to a second drain stack that is not vented? A lot of stuff in this house seem cobbled together so anything is possible.

I'm also a little concerned about that unused floor drain that you mentioned that has no trap but drains into gravel below the floor. That's basically an opening to under the slab, and since you mentioned a backed up septic system and contaminated soil I'm wondering if this area isn't a breeding ground for all kinds of nasty bacteria.

Why don't you try this. Buy a cheap cigar, turn on the dishwasher and/or shower, then go downstairs with the cigar, light it, and hold it next to the floor drain, then the shower drain, and all along the edges of the shower pan. If this part of the drain system is unvented then air will eject from one or more of these openings, and you ought to be able to see air movement with the cigar smoke.

Redwood might be able to help you with the brand of cigar to buy. :D

Redwood
10-27-2008, 06:16 AM
Redwood might be able to help you with the brand of cigar to buy. :D

I wouldn't have a clue...
I don't smoke cheap cigars and don't advocate smoking in customers homes...

Southern Man
10-27-2008, 08:59 AM
Here's where I'm going with this floor drain that empties into gravel below your floor slab.

http://www.fantech.net/radon.jpg http://www.fantech.net/radon.htm

Regardless of radon in your basement or not, this type of fan could be used to vent that space. You should have gravel under your slab as well, so this would put the entire area under the slab under a vacuum, which may take care of the odor problem entirely.

I've had one of these running for 8 years to remove radon from my house and never had a problem with the unit. I just installed a second one at my cabin to take care of radon there. The most difficult part of the installation was cutting a hole in the basement wall for the discharge.

Maybe you can connect a big shop vac to that drain, set up the machine outside with a long hose, and run the shower upstairs to see if the concept works.

artistsnature
10-29-2008, 06:50 PM
I'm a little concerned about the vent size and location (below the highest bathroom) but if the stink occurs when you're running only the dishwasher or shower upstairs then I don't see how that could be the problem. If it was then the stink would occur when other units were draining.

Is there a possibility that the dishwasher and shower are connected to a second drain stack that is not vented? A lot of stuff in this house seem cobbled together so anything is possible.

I'm also a little concerned about that unused floor drain that you mentioned that has no trap but drains into gravel below the floor. That's basically an opening to under the slab, and since you mentioned a backed up septic system and contaminated soil I'm wondering if this area isn't a breeding ground for all kinds of nasty bacteria.

Why don't you try this. Buy a cheap cigar, turn on the dishwasher and/or shower, then go downstairs with the cigar, light it, and hold it next to the floor drain, then the shower drain, and all along the edges of the shower pan. If this part of the drain system is unvented then air will eject from one or more of these openings, and you ought to be able to see air movement with the cigar smoke.

Redwood might be able to help you with the brand of cigar to buy. :D

BRILLIANT!

Actually, it's the upstairs shower, the dishwasher OR the washing machine that cause the stink - all of which (plus the basement lavatory) drain into the same 1.5 " horizontal pvc pipe that leads directly into the bottom of the waste stack.... I'm not sure where the vent stack comes off the waste stack, but I suspect that it connects to the main floor fixtures (it comes out the roof above that bathroom).

The basement bathroom was definitely a shoddy job put in 15 years ago - I just replaced all the fixtures after tiling the floor, including the shower stall. The stall itself was just a thin piece of linoleum glued to the studs on the cinder block - no insulation, no backer board (talk about a cold shower!). When I first bought the place a year ago, the shower handles had been taken off and shelves installed in the shower - above the 3 inches of dried excrement!

Anyway, I assume that the shower is tied into the main waste stack, so it would vent up there, right? Is it possible to add a vent stack to the shower? Is venting into the wet waste stack the problem? (I'm getting out of my league here...).

I will try the cigar idea, but just FYI the house failed the radon test, too, and I have a system installed....

Thanks again!