I bought a 15 year old house about a month ago and just had the septic tank cleaned out. According to the serviceman it was in pretty good shape. My problem is that there is an septic odor coming from the tank area about ten feet from my house near the top of the tank. It is not noticeable at all times. I only seem to notice it when temp get colder at night and sometimes when it rains. 

I think that my line from the house to the tank might be damaged and the area around the tank is saturated. 

Any suggestions....