View Full Version : sewer gas/wax ring failure

Gail S
01-09-2005, 09:38 AM
HI all, I am a new user to this (or any )forum so please excuse and gently correct any social gafs I make. I have a mobile home (a '94) that has within the last few months been plagued with sewer gas. It seems to be episodic, worse on weekends during the day, and weekdays in the morning and in the evening. I have had plumbers here twice to correct this. The first one changed an in line vent. That didn't help. When the second one came I had removed the wall panels to expose /examine all of the plumbing lines and the vent line behind the toilet. There is only one vent through the roof and it runs up right behind the toilet. He inspected that (ok) snaked the vent(no clogs) changed the wax ring on the toilet and replaced the cheap inline vents with studdor vents . He said the ring had been leaking sewer gas even though there had been no water leaking. That was good for about a week and now the sewer gas is back again. The toilet is tight and secure to the floor. My questions are; what would cause a ring to fail again? Is there something eles that might work better? Could my vent be of inadquate size (it does meet code)? Could this be caused by the new pumping station that was put in up stream from me. I realise this is a very long piece but I am desperate I can't stand to be in my home. Thank You, Gail

01-09-2005, 10:29 AM
Someone should be able to do some kind of smoke or peppermint test to find out exactly where the odor is coming from.
If the wax seal has failed, and that is where the sewer gas is coming from, there should be a reason. You might try a Fluidmaster wasless gasket, rather than a wax ring.
Have all the traps been checked to make sure they weren't being siphoned?
A partially clogged drainage line can cause traps to siphon. Do you have a drain that is not used much (like a washing machine)? The water can evaporate, allowing sewer gas in. Did the odor coincide with the installation of the new pumping station (I don't generally believe in coincidences)?
Are you absolutely sure that it is sewer gas?
This happening at specific times on different days is rather strange. I notice that it rather seems to coincide with "off time if you work a M-F 8-5"?
The Pipewench

Gail S
01-09-2005, 07:11 PM
Thank you, Deb the pipe wench, for responding to my questions. I will look into having the Fluidmaster wasless gasket installed as well as having a smoke test. I sometimes work out of my home which is why I was able to note the times of day of the occurances. In fact it is now 9:45 pm, my toilet just made a noise as if it were starting to flush itself for a few seconds (it does that every now and again I think its haunted) and now there is a fresh plume of stench. The traps seemed to be fine when they were checked and all are used daily, as for the washing machine I pour water down the drain if I haven't used it for a day or so. I have been living here for 3 years, the pump station started this summer, the problem started this summer. Its just a thought. Thanks for your input I really appreciate any and all info I can get.

01-09-2005, 08:28 PM
This is just a wild guess...is it possible the pumping station is filling up the line with the volume and then sucking the traps? Would a check valve make a difference?

Gail S
01-10-2005, 08:23 AM
Hello Jim, thank you for your reply. The question of sewer line volume has been playing in my mind too. I live at the bottom of a long steep hill and am the last house on the line before it goes into the treatment plant. All of these issues are new to me and I don't really understand the engineering behind it but is what you suggest possible? Can you tell me more about this check valve. Is this the same thing or similer to the studdor vents that are in the plumbing lines? Where would I find a check valve? How would I know if I have one or not. If I do have one how would I inspect it to know if it is working? Is it something I can have a plumber install? Would the check valve prevent the traps form being siphoned, if this is the problem? This is turning into such an education for me, I trully appreciate the information I have recived. Thank You, Gail

01-10-2005, 09:30 AM
I'm not a pro, I brought it up as indicated as a guess. A check valve is not the same as a Studor valve. A check valve is a one-way valve to prevent sewage from outside of the house from coming in. Each of these valves are one-way, but the Studor (air admittance) is to let air into the system so it can vent properly, the other is to keep outside sewage from coming into the house. My thought was if the line was indeed full, when the pump turned on, there being no air in the system, it could siphon out stuff. I don't know if this is possible, but I brought it up as a thought. I'm interested in the answers, too.

01-10-2005, 09:45 PM
When your toilet seems to be flushing itself, it is simply refilling the tank with water--check your flapper, that is the most likely place to be losing water (did you mention this to the plumbers?). But it is virtually impossible for this action to be creating any kind of sewer stench.
You indicated that the traps seemed to be okay when they were checked. Were they checked when the odor was present? If the traps have water, the pump station is not siphoning the traps. If there is no water in the traps, that is where the odor is coming from. And if the pump station is the cause, we will go from there. I doubt this for several reasons--others would be affected, air would be pulled from yours and others plumbing vents, the system would have been sized to prevent this, etc, etc.
I am also a little confused about the pump station. Where is it located and where does it pump to? I am a little confused as you indicate that you live at the bottom of a steep hill (does it pump uphill from somewhere and then run downhill by gravity to a treatment station????).
I don't think that a check valve is going to take care of your problem, even if the pump station is siphoning the traps, which I don't think is likely.
Were the plumbers there at the times when the odor was present?
The Pipewench

Gail S
01-11-2005, 10:10 AM
Hi Deb, Thanks for your reply. I answer to your questions. When the plumbers were here the smell was barely noticible, not the full on stink-a-thon that it can become. Yesterday the squiddle fumes were so bad even the dog couldn't stand it. I took your sugestion to heart about possibly a partially clogged drain so last night I treated the bathroom sink and and tub with liquid drain cleaner. It is now noontime and so far so good, no smell. They do drain better than they had (I thought they were just normally slow)
The toilet filling itself only started after the last plumber was here and replaced the wax ring it doesn't do it very often, maybe once every 2or 3 days.
You've basically got it right about the sewer lines. This is a rural area being quickly developed. I live in the oldest part of town which has always had sewer service and is at the bottom of a hill. All of the lines have been gravity fed to the plant nearby. In the last year there has been an effort to get the rest of the town as well as the new developments on the far side of the hill on to the lines. So it is pumped up over the hill on the far side then runs down by gravity past my house. I have heard a few other folks mention that they were now getting odors but I don't know the nature of their problem. I have a nieghbor 2 doors up who gets odor from her shower drain but again I don't know if they have other plumbing issues going on.
I will check the drains first from now on when there is peak stink to see if they are being siphoned out. I didn't know that it was possibly to do that before. This is becoming such an education!
Thank you for so generously sharing your knowledge, I am so glad I found this forum. Gail

01-11-2005, 07:48 PM
In my area, mobile home sewer odors are most often from the connection from the mobile home to where it is tied into the sewer. Often they just use a flex line stuck into the pipe. It is not an air tight connection. When other sewer movement occurs in the area it aggitates the odor and up it comes through the floor. Sometime I find sewage water under the home.

Gail S
01-12-2005, 06:35 AM
Hello Lonnie and All, In answer to your question the plumber checked under the house first, there is no leaking. I am not in a park but on my own land with a full concrete foundation and all pvc lines and conections underneath. I did how ever have a strange thing happen last night. As I have said before this seems to be eposodic and in the wee hours of the morning it occured again,and I had been so hopeful that I had fixed it yesterday. AT 3:30 this morning I was awoken by the smell filling the house. I lay in bed thinking this can't be I thought it was fixed! Once again the smell was coming from the bathroom area. There hadn't been a plumbing fixture use in the house for 5 or 6 hours. In no mood to start checking traps I just dumped a glass of water into the sink, tub, and washer drain and went back to bed. The smell stopped immediately. It is now 9:03 and it has not come back. My question is why would the traps become empty in the early morning hours?
What would cause this when no plumbing fixture had been used for several hours?(all of these had been used in the last 24 hours) How do I prevent this? Thanks to all for the input.Gail

01-12-2005, 07:14 AM
Good for you detective of foul odors. Seems you have identified that you are loosing your water in one or several of the traps which allows odor to infiltrate. See if you can identify which one. We loose trap seals from a lack of a vent to break siphonage. I feel that this can occur from sewer main movement outside this structure but other plumbers may not agree with me. I think this happens with undersized mains that are vented through the house. I would relate it the pumps. Not that it's the pumps failure but that it aggravates an existing condition in your mobile home that wasn't present with a gravity line.
I already owe hj an explanation on house traps in my area, but I have had enough conversations to believe at a minimum that occupants have had sewer odors in a house, that have been cured by the installation of a house trap. I feel this principle possibly relates here.

Gail S
01-12-2005, 08:37 AM
Thank You Lonnie what an idea! A house trap! I am imagining this as a very large p trap under the house. Do you think this would stop the smell from coming in? MY questions are. #1 If the other traps that are already in the house are being siphoned couldn't this be siphoned as well? My concern is that I 'll spend a great deal of money havin this put in, only to find myself having to pour gallon buckets down the drain at 3am instead of glasses! #2 My other thought is freezing would there be a way to keep this from freezing ? I have to have heat tapes and insulation on my water lines. Is this something that could be heat taped. The space under the house is not heated and is kind of like a minnii basement for migets. Its all concrete and easy to get around in but COLD. As an asside I just found out about a neighborhood forum where the question of sewer smell has come up, I have placed a querie to see if any one else is having this particular problem. Thank You, Gail

01-12-2005, 10:13 AM
Just reading all the comments on this issue. Rather interesting.

Problem started with the operation of new treatment plant.

You are located at the bottom of a hill, and the last connection before the treatment plant.

All your traps are emptying out at the same time, I suspect that includes the toilet, not that the toilet is flushing its self by emptying the water closet (tank).

Forget the plumbers, contact whoever is responsible for the sewage system in your county (town). Sounds like they either have a design flaw as to where you are tied in or have an operation problem or both.

It would sound like the main is backing up and then creating a sudden suction which is more than the vent in your home can handle, thus it is pulling the water from your traps. Depending on the amount of suction a second vent may or may not be of help. It is probably happening when they switch holding tanks or have a large pump kick in, or........ a pump(s) upstream kicks in and puts a large volume down your way, or.......

They may give you the run around for a bit but, I would be willing to put money on the problem being theirs.


Gail S
01-12-2005, 10:14 AM
I just got off the phone with a builder friend of my. After relating my plumbing problems, hecame up with another possible solution. I want to run this idea past the knowlegable folks of this forum. His suggestion is, instead of a house trap, which he felt would be sucked dry the same as the others, it would be best to put in an additional vent stack. His theory being that if I put this in as close to where my drain line goes out to the street and make it of sufficient size it will relive any suction placed on my traps. The way my house is oriented this could be easily done, would be down river from all of my fixtures and could go up the outside of the house above the roof line. Does anyone have any experience with this sort of solution? Any thoughts on it? Good idea? Bad idea? Gail

Gail S
01-12-2005, 10:28 AM
Hi Paul, I just saw your posting. I have wondered if that could be part of the problem. I am trying to chase down any potential flaws in my system before I got to the sewer board with a complaint. Otherwise they could rightfuly say the problem is all mine.Thanks for the input, Gail

01-12-2005, 10:37 AM

If your system is to code, which your plumber should be able to quickly tell you, being he / she has already looked at your layout. I would not drive myself too crazy, the timing and facts seem to point in one direction.

However, your biggest problem will be finding someone on the board with the ability to listen and comprehend what you are saying. One thing that always seems to get their attention, is if they think you are willing to share your situation with a local newspaper. Our small town politics stink more than the sewage.

Reread my comments above, edited it.

Good luck.


01-12-2005, 01:16 PM
Don't spend money on a house trap. I did not mean it as a recommendation but as an approach to understanding the problem. It is most likely that you need real vents to the atmosphere instead of Automatic Air Vents (AAV's), even if they are Studor's. A house trap is a 4" running trap and therefore stronger than the tubular sized 1 1/2" traps. If the house trap does get sucked dry then you still have the fixture traps protected and the house trap water gets replenished with the next use.
Freezing may be an issue if your frost line is deep. How deep do they put your water services? In some jurisdictions the house trap is located at the main but in mine it is anywhere on the property and I am always below my 2 foot frost line. Heat tape is unreliable and you need a maintenance free solution.
Mobile homes are usually not under a plumbing code they have a national manufacturing code. If you are in a mobile home park with a private system then you are probably not under a jurisdictions authority.
If the sewer main is at fault and a house trap could cure then your neighbors should be having the similar complains. Not necessarily at the same degree.

Gail S
01-12-2005, 03:45 PM
Hi Lonnie, I don't know if you saw my post script to my last entry. In short, a builder friend of mine has suggested instead of a house trap I might be better served by putting in an additional vent, a much larger one than I have ( he feels its too small) and placing it right where the pipe goes out to the road. This would be down river form all of my fixtures. His theory being if we put in a vent the same size as the pipe going out (3" I think) the amount of suction on the pipe would then be the same as the ventilation available:ie 3"of suction= 3" of ventilation. The house trap, while a good idea sounds a bit more involved. I believe water lines here are placed 4' deep to avoid frost. I am not in a park,I am on my own land. Do you think the additional vent would work? Have you had any experience with this? Anyway he said for not much money and an afternoons work we could put this up along the out side of the house and see if it helps. Do you have any thoughts on this? Thanks Gail

01-12-2005, 07:37 PM
I do believe the outside vent will work and not cost much money but DebthePipeWench has more experience than I on septics and I will defer to her opinion if it differs.