I have a similar problem with my septic system. It seems to occur more often in the cold/windy weather, but I suspect that my washing machine may be purging its own trap also. Could environmental conditions like wind, cold air, or humidity create enough back pressure in the vent pipe to force the methane gas back down into the system? If so, how does the smell get into the house ? or why does a dry trap yield an odor in the house? It seems that there is a breech in the system that is there all of the time but the odor comes and goes occasionally. Please help!!!! Thanks neil : : : : Thanks to the both of you for your comments. I havent followed up on Colins as yet : : : because of the difficulty of getting at the pipes. I may have to remove some wallboard : : : to see part of it and the 4part between the laundry room and the crawl space is under : : : the concrete floor.: : : Scott, Your link gave me the dreaded 404. In answer to your questions, we bought the : : : house (14 years old) 2 1/2 years ago. Knowing nothing about septic systems, we had it : : : pumped immediately and again 7 months ago*. The odor has always been a problem but at : : : times it is far worse than others and it usually is most noticeable when laundry is : : : being done. Sometime a long shower (as in bathroom) will result in the odor appearing.: : : The first guy was just a truck driver but the second said there seem to be little : : : bacteriological action.: : : It is possible that one of your traps is not vented : : properly and is getting syphoned out. You should never : : get methane gas from your sceptic system into your : : house. Go around and make certain all of your traps : : are full. If they are, the ordor should go away and not : : come back, unless one gets emptied out again. If you can : : figure out which one is being emptied out, it should : : be fixed immediately. Methane gas back in the house is : : very dangerous.
