Is there a better way to get rid of the odor?? In a word,move. Judging from your few statments,I believe A. sewer lines are not properly installed,if they were,water would not stand in lines long enough to freeze. B. How did sewage get outside line unless lines were not installed water tite? If lines were water tite with bellys that froze,they busted. Did they replace busted/leaky line? C. the spillage is owner's responsibility to have experts clean up well enough so it no longer stinks D. The hvac return is leakey and pulling air from crawl space. or even worse ,return has sewage inside it. Is it in your rental agreement that you will go on line seeking free diy advice instead of owner taking responsibility for maintainance?

Thanks, kiem1. I was going by what maintenence people were telling me. The next door neighbors were having problems too (sewage backing up into their house, couldn't flush toilets or bathe), so mgmt called outside contractor who fligured out that there was a plugged sewer line out at the street. While they were over at the neighbors I had them to check out the area where the odor was coming from under my house and they notified mgmt of the problem..I agree that maintence did blow me off, instead of hiring a plumber to look into the problem from the outset. Anyhow, they cleared the plugged line and odor spontaneously disappeared.