Last fall we pumped the septic tank. Shortly after the house began to smell like sewer gasses. No leaks evident. It went away, but now that it is cold again it has returned. Health reasons aside, this is a gross problem and with the cost of heating oil I am not leaving a window open all winter.
Without any evidence of a leak or clogged vent pipe (in roof), does any one out there know how to find this, inexpensively?