Sewer Smell Outside of House

[Dublin]

Hiya Folks,
I have a small cabin in the woods which uses a septic system. We visit it maybe once or twice a month. I have to admit, it hasn't been pumped out in a few years. The last couple of years, I've noticed sewer gas odors after we shower or do dishes etc.... I have a horizontal vented gas fired heater and suspected bacterial growth in the exhaust that but that doesn't appear to be the case. I believe I am getting the odors from the roof top vent and the odors are definitely stronger on that side of the house. I'm not getting any odors in the house. I plan to have the septic pumped this summer but I don't think that will help (or maybe it will?). I've seen the carbon type filters that slip over the top of the vents but not sure if those are effective or not? It just seems strange that for 10 years, there were no odors and only in the last couple of years have I noticed them. Do any of you have any recommendations of things to look at? Do the vent filters work or just snake oil?
Thanks very much,
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[RTF]

Sounds to me that the septic tank is full and needs to be pumped out. Your field lines may be clogged as well and may need replacement.

[Dublin]

So not discrediting your opinion at all, just trying to understand. If the septic were full or the drain field has failed, shouldn't I get sewage backing up into the house? I have a septic system at another house and this very thing happened as the drain field failed. Had to install new lines to another location to rectify the issue. Just curious. Thanks very much.
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[dexter]

I agree with RTF, but as for the reason that it is not backing up, it's probably simply a matter of the frequency of use. If you were there all of the time, it most likely would be backed up. The sludge that builds at the top of the tank will slow the flow, but not necessarily stop it completely. The real problem though is when it gets thick enough that it starts being pushed out into the field, which, when left unchecked, plugs the lines, so that the liquids cannot leach into the field. That is when the $$ start to flow.

[EDJ13]

I'd be leery of filters and such on top of a vent stack. There's not much pressure there anyway and I don't think you'd want to interfere with the air flow.
You could try and extend the stack a couple of feet higher above the roof. That should be cheap and might help.

[Dublin]

Thanks guys for the explanations. Better get it pumped and see what happens. Given it has been awhile since being pumped, I have visions of a backhoe visiting soon! :(

Thanks much,
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[RTF]

It's not only my opinion, but I had a similar situation at a lake house I owned. When weekend use turned into everyday use we experienced similar problems. Old system became clogged and it had to be replaced.

[Dublin]

Thanks folks. Not looking forward to opening it up tomorrow! Where this house is, rates are like double what they are in the city.... :(
Cheers,
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[Dublin]

Well had the septic pumped. Company indicated the system is working fine and the leach field has not failed so that's a bit of a relief. We did find that one of the cleanouts has a piece broken out of it where the cap screws on. They seem to think that may be allowing air into the system and ultimately back up the vent. I'm not so sure but I'll get it repaired nonetheless. Given it was just pumped and it was just me there, it's far from full so didn't get any odors while there. Will just have to see how it goes when it gets full again and I've repaired the cleanout pipe.

One interesting thing about the whole system however is the top of the septic is only about a foot below the ground. This is located in the mountains of NM where the frost line is 48". I would think the contents would freeze in the winter but the guys there didn't seem to think so. My septic at home is down around 3' with a frost line of 18" so I thought it was odd.

Anyway, thanks for the inputs.
Cheers,
cc