Pond Boss Forums GENERAL QUESTIONS Pond Boss ...that stinkin' sump pit

Given that the problem has been occurring for a couple of years and the septic tank got a passing grade last Spring, I think the septic line ("soil pipe", for those who come from plumbing families like mine) having cracked is the most likely of your two septic leak scenarios. The place it would probably do so is at the house excavation/unexcavated yard boundary, due to settling and the differences in soil density. From which point it would have an easy shot down to the perimeter drain.

I suppose the line might also have cracked farther along and be seeping back on itself toward the house, but that should be uphill. I distinctly remember my Dad teaching me "Septic flows downhill" at an early age, both verbally and nonverbally.

Mind you, we could still be full of it on the septic theory. You could dig a little test hole above the septic line where it leaves the house and see if you get any telltale odors as you dig to the pipe.