Q: At a northern lakeshore home used intermittently during the winter months, some of the plumbing vents were reported to be dry. This allowed septic tank gases to seep back into the house. This condition was detected when the house was opened for a chilly weekend visit. Why did it happen?A: My friend and colleague, Jim Anderson, who recently retired from the University of Minnesota, reported this problem to me. After retiring, Jim and his wife, Chris, spent much of their summer building a new year-round home by a lake in northern Wisconsin. The home required a septic system, so
