Toilets Burping Septic/Sewer Gas...

Users who are viewing this thread

Messages
51
Reaction score
1
Points
6
Location
North Carolina
I wasn't sure what forum to post this under, as my problem potentially pertains to a number of different areas (toilets, septic, venting, etc.) House is 11 years-old. We bought it 5 years ago and used it as a vacation home for 4 of those year. We started living in the house full-time almost exactly a year ago. About 6 months ago, my wife and I noticed a sewer gas smell wafting up from our twin bathroom sinks when we were using them. Shortly thereafter, the toilets (master bath AND guest bath) started "belching" the same gas when they were flushed. The gas comes from the jet, and is enough to seriously smell up the bathroom and several feet down the hall. As far as we can tell, the gas is only coming from these fixtures.

We have a well and septic system. Thinking the septic tank might need pumping, I contacted a local company. Even though the tank hadn't been pumped since we bought the house, the man who pumped it didn't say there were any issues. It wasn't full, and we've never had any backups or soggy areas in the yard. We used to get a lot of down-drafting, so you would definitely smell it outdoors when someone was taking a shower or doing laundry. FWIW, we no longer smell the sewer gas outdoors like we used to.

That line of reasoning is what got me on the roof with a 20' pipe snake and a garden house. I snaked both roof vents and ran water down them for a few minutes- nothing. I even went so far as to cut the vent pipes in the attic, so I could snake the vent where it branches off to the individual fixtures in the house- nothing.

I went under the house to take a look at the piping. There's a main drainage line that has two clean-out plugs. Expecting to be choking on sewer gas, I opened up the pipe closest to the septic tank- nothing special/no gas smells. I opened up the plug at the opposite end of the line and shined a flashlight down it- nothing special/no clogs. My wife flushed the toilet while I had the clean-out plug open, and it seemed to drain just fine.

I recently cleaned out our twin sinks and flushed the line with one of those balloon things that attaches to a garden house. The pipes were pretty stinky, and the water that flowed out of them reeked of gas. It's still too early to tell if the gas will come back...

I discovered a Studor vent under the kitchen sink. I doubt this has anything to do with my problem, as we haven't had issues with the kitchen sink. I went ahead and replaced it anyway.

At this point, I AM COMPLETELY STUMPED!!! Where is the gas coming from? If it's an issue with the septic system, why are we only getting gas at certain fixtures in different parts of the house? We have high iron in our water, so I was thinking maybe we have bacteria in the piping that is creating the gas, but I don't understand why we wouldn't have gas in all the pipes. If anyone can shed some light on this issue, I would be grateful. Should I call a plumber or call the septic company back? If my issue is the septic system, is there anything that can be done other than digging up the whole yard?? This problem has been driving me crazy, and it really stinks when we have guests...
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,770
Reaction score
1,190
Points
113
Location
New England
Do all of the drains work without backing up?

IF the venting system is not done properly, it could be blocked...the fact that it drains is not an absolute indication that it isn't full. It must be sloped properly so that a section doesn't act like a trap. A squirrel or other small animal might be at least partially blocking things.

When one of the sinks starts to smell, run a little bit of water and see if it stops. If the vent system is not correct, their trap can get suctioned dry, allowing gasses to escape.
 

Smooky

In the Trades
Messages
2,299
Reaction score
152
Points
63
Location
North Carolina
Maybe the odor is coming from the overflow in the sinks. You could put bleach water in there to see if that helps. Also a picture of the plumbing under the double sink might reveal some clues.


I owened a home in the easten part of the state and hydrogen sulfide would come out of the water and caused a bad odor in the house when the washer was running or the shower was on etc.
 

Reach4

Well-Known Member
Messages
38,796
Reaction score
4,412
Points
113
Location
IL
Here is an idea in case the other things are not working for you. I have not actually tried it. Try it only if it makes sense to you. Suppose you take some transparent (or close enough to clear) tubing. Could be 1/4 to 5/8 ID I would think. Shove one end thru the toilet exit enough to get up and the end past the standing water level in the toilet. Blow firmly into the clean end to remove any water in the tube.

Put the clean end into a glass/jar of water, at least 3 inches into the water. I don't expect a siphon to form, but I guess the glass should be higher than the water level in the toilet just in case. The water level in the tube should match the water level outside the tube if the venting is working. An inch of mismatch may not cause a problem, but you should never see 2 inches of mismatch. Then run some water in the sink or do other plumbing things that you think have triggered the smell in the past.. If the water level in the tube drops below the level in the glass, there is pressure in the sewer line. If the tube bubbles, there is lots of pressure.

You could maybe run this tube through the sink trap instead of the toilet. That would be harder, because the sink trap has a tighter radius.
 
Messages
51
Reaction score
1
Points
6
Location
North Carolina
Do all of the drains work without backing up?

IF the venting system is not done properly, it could be blocked...the fact that it drains is not an absolute indication that it isn't full. It must be sloped properly so that a section doesn't act like a trap. A squirrel or other small animal might be at least partially blocking things.

When one of the sinks starts to smell, run a little bit of water and see if it stops. If the vent system is not correct, their trap can get suctioned dry, allowing gasses to escape.

Thanks so much for the reply- all of the drains do work without backing up (we've never had a backup or any issues like that). I was wondering if the venting system could have been installed wrong, but the house has been fine for 11 years (or at least the 5 that we have owned it). The other strange thing is that the gas smells are coming from sections of pipe at almost opposite ends of the house. If there is a pocket of trapped gas, it's happening in two different locations without affecting the drains in between.

We've also never had any issues with water being siphoned from other drains- we only get the gas smell from drains at the time they are being used....
 
Messages
51
Reaction score
1
Points
6
Location
North Carolina
Maybe the odor is coming from the overflow in the sinks. You could put bleach water in there to see if that helps. Also a picture of the plumbing under the double sink might reveal some clues.


I owened a home in the easten part of the state and hydrogen sulfide would come out of the water and caused a bad odor in the house when the washer was running or the shower was on etc.

Thanks so much for the reply- I thought about the overflow, but that wouldn't explain the toilets :( On the plus side, though, the gas has yet to return to the double sink that I dismantled and cleaned... That makes me wonder if we are having hydrogen sulfide gas from the water as you suggested... Our water is absolutely terrible with iron/acidity, so that wouldn't surprise me. It still doesn't explain why we're not having the issues at other locations or why it just started now...
 
Messages
51
Reaction score
1
Points
6
Location
North Carolina
Here is an idea in case the other things are not working for you. I have not actually tried it. Try it only if it makes sense to you. Suppose you take some transparent (or close enough to clear) tubing. Could be 1/4 to 5/8 ID I would think. Shove one end thru the toilet exit enough to get up and the end past the standing water level in the toilet. Blow firmly into the clean end to remove any water in the tube.

Put the clean end into a glass/jar of water, at least 3 inches into the water. I don't expect a siphon to form, but I guess the glass should be higher than the water level in the toilet just in case. The water level in the tube should match the water level outside the tube if the venting is working. An inch of mismatch may not cause a problem, but you should never see 2 inches of mismatch. Then run some water in the sink or do other plumbing things that you think have triggered the smell in the past.. If the water level in the tube drops below the level in the glass, there is pressure in the sewer line. If the tube bubbles, there is lots of pressure.

You could maybe run this tube through the sink trap instead of the toilet. That would be harder, because the sink trap has a tighter radius.

I'll have to get some tubing from Lowes and give this a try- I'm not 100% sure if I understand what I'm looking for with this test, though? The gas that bubbles up from the toilet jet comes up with some force (makes a bubbling sound when you flush the toilet), so it would seem that there is definitely some kind of pressure in that line to force that gas up (or would that be a siphon effect when the toilet is flushed?) So confused...
 
Messages
51
Reaction score
1
Points
6
Location
North Carolina
Iron bacteria might have been causing the odor:
http://www.garreltswater.com/water-quality/iron-bacteria/

Hmmm... That may be the problem- especially if it only occurs in certain fixtures. The sink pipes that I pulled from our master bath for cleaning definitely had some black sludge on them. The smell hasn't returned, and it's been a couple days, since I cleaned it. I'm thinking maybe I should disconnect one of the toilets and see if I can clean that piping somehow....
 

Reach4

Well-Known Member
Messages
38,796
Reaction score
4,412
Points
113
Location
IL
Hmmm... That may be the problem- especially if it only occurs in certain fixtures. The sink pipes that I pulled from our master bath for cleaning definitely had some black sludge on them. The smell hasn't returned, and it's been a couple days, since I cleaned it. I'm thinking maybe I should disconnect one of the toilets and see if I can clean that piping somehow....

Black sludge can come from sulfur bacteria. Flushed your water heater in the past few years? If you can see what comes out, it might be interesting. Try draining a couple gallons into a white bucket as a sample.

However I don't think that would be associated with your burping symptom.
 
Messages
51
Reaction score
1
Points
6
Location
North Carolina
Black sludge can come from sulfur bacteria. Flushed your water heater in the past few years? If you can see what comes out, it might be interesting. Try draining a couple gallons into a white bucket as a sample.

However I don't think that would be associated with your burping symptom.

Yeah I used to drain it every time we left after a vacation. I would usually get some rust-colored water for the first 10-15 seconds, which didn't come as a surprise with our crappy water. I agree, though, I don't think that's the issue, as the toilet water is just cold water... I guess I'm going to pull up the toilet in the guest bath and give the pipes and everything a good clean to see if that does anything....
 
Messages
51
Reaction score
1
Points
6
Location
North Carolina
So, I removed the toilet in the guest bathroom. I expected to be choking on gas when I broke the wax-ring seal, but I didn't smell anything. Nothing looked especially abnormal- there has always been some slimy black stuff in the tank, which I assume is iron bacteria. It has a very faint odor, but I never smell the rotten egg gas when I take the top off the tank. The only thing that looked a little nasty was the wax ring. Around the inside edge of it was a thick layer of stuff that looked like congealed fat. I expected to see some nastiness on a 10 year-old wax toilet ring, though. In any case, I cleaned the tank, replaced the ring, and replaced the gasket between the tank and the bowl. I guess I'll wait and see if/when the gas smell comes back...
 
Messages
51
Reaction score
1
Points
6
Location
North Carolina
I just wanted to update my post for others who may encounter this issue in the future... It has been almost a week, and the gas smell doesn't seem to have come back to any of the fixtures where we were smelling it. Only time will tell, but I'm trying to figure out what solved the problem :confused:. I flushed the sink lines, replaced the wax ring on 1 toilet, and cleaned that toilet tank. I didn't do anything to the other toilet, though, and I'm not smelling anything there... I DID replace a studor vent that was under the kitchen sink (at the end location of the main sewage line). Is it possible that replacing the studor vent under the kitchen sink affected the venting at other fixtures? Might have to start a seperate post for that question...
 

Reach4

Well-Known Member
Messages
38,796
Reaction score
4,412
Points
113
Location
IL
Is it possible that replacing the studor vent under the kitchen sink affected the venting at other fixtures?
"Burping" implies pressure from inside the sewer system, doesn't it? If so, since an AAV only admits air, it will not relieve pressure.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks