septic stink in basement - help!

Steve_Miller · Dec 2, 2007

hazmat said:
We are getting a septic smell in the basement. Smell is more noticeable after a shower. No leaks can be found. On advice of my plumber, I had the septic tank pumped.

I imagine if it were a plugged vent, that I'd be having draining problems in the rest of the house.

Thoughts?

A couple of years back one of the vents in my attic must have froze. After someone would have a bath and drain the tub, the toilet would start bubbling. Took me a few times to realize that the water draining away was creating a back pressure which forces the air back through the weakest link, which in my case was the toilet beside the tub. I got up on the roof and poured a bunch of hot water down the vent pipe. This worked for a day or two and it came back again. Did it again to free it up and looked in the attic at the maze of pipes tied together to allow just one pipe to exit through the roof. One of the long runs of pipe had enough of a sag to it to create a drop that would allow water to accumulate in and freeze enough to block the vent. Just propped it up to allow the water to drain away and viola the bubbling was gone. At first I thought a bird or something may have been overcome by the sweet aromas an fell into the vent pipe blocking it, but the hot water trick seem to free it the first time, so explored that avenue.

Brings back a memory when I was a teenager, we had a black bird fall into the vent pipe at my parents home and survive. My mother was in the basement doing laundry and could hear this rustling somewhere, my father wasn't home at the time so I listened for a while and determined it was in the drain from the toilet/tub area . There just happened to be a clean out right there so I made sure no one flushed while I was removing the plug, I held a bucket up close as I wasn't sure what would run out, nothing other than a few drops and then pulled the plug away and out jumps this blackbird all covered in you know what and attempts to fly away. Well his flying capabilities were not that great being soaked with you know what, well I ended up with a face full of this and ended up being covered from head to toe by the time I caught him. We washed him up and kept him for a day or two and then let him go, he seemed none the worse for wear and flew away. Those must have been the good old days where bigger was better as the vent pipe was a 4" pipe all the way up and out through the roof. The basement piping was all old ductile iron with packing and lead filling. That's my story for the day, hope it kills a few minutes of your time as it killed a half hour for me just trying to type this much.

Steve

Tig · Dec 2, 2007

Vent pipes are 4" in cold climates to be resistant to blockage by frost build up. During extreme cold spells I have had my 4" vents blocked by frost.

chipsndust · Dec 2, 2007

I agree with other posters that there is probably a clog in a vent somewhere. There may be a vent pipe in an interior wall that you haven't found.
Another possibility (this happened at my camp) if there is a drain line that is infrequently used (in my case it was the washing machine) the water in the trap will evaporate, leaving a path for gasses.
Good luck

davitk · Dec 2, 2007

chipsndust said:
if there is a drain line that is infrequently used (in my case it was the washing machine) the water in the trap will evaporate, leaving a path for gasses.

Martha Stewart tip of the day: place a tablespoon of vegetable oil in a seldom used trap; it will cover the water and slow evaporation.