Re: Sewer smell in house is HORRIBLE
Posted by Gail Mathias on March 02, 2004 at 07:54:45:
In response to Re: Sewer smell in house is HORRIBLE
: The Sewer gas may be coming up from the drain lines such as under your sink. This gas is normally stopped by the water in the P-trap between the sink and the drain line. Why would the P-trap not be filled with water? One answer may be an unused sink such as in a guest bathroom or utility room which has gone unused so long that the water in the P has simply evaporated out. Another answer is that an air vent has become plugged. Without a clear air way, the vacuum of the water draining away pulls air through the appliances, this vacuum sucks the water out of the P-trap leaving an open path for the sewer gas. If this is the case, going up on the roof and snaking out the air vent will restore the air flow.

: Good luck

Everything said by this person turned out to be the solution to our problem (the sewer gas was affecting five commercial tenants on the ground level). For two winters, and only when the temperature was bitterly cold, the smell of sewer gas was terrible. A plumber said that the P-traps must be dry and so everyone was pouring lots of water down their floor drains every week or so. But the smell kept returning. Finally, I went up in the attic (with a different plumber) and he tapped the vent throughout its length to try to see if ice had built up and was blocking the vent pipe. The pipe had a short horizontal section where ice had completely blocked it, so he cut off the vent at this point and it took me 24 hours to defrost it, using warm water and a portable heater (not too close to pipe). After the vent was unblocked, the smell disappeared and never came back, but the long term solution is to eliminate that horizontal section where water collected and froze. Good luck.


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