Hello, We live in a flatish area in northern Illinois. Our basement sump pump discharges into corrugated 4" black plastic tubing, that runs off about 70 feet toward the edge of the property, where the grade is about 1-2 feet lower than at the foundation. I've never found an actual discharge...

The sump well in my basement has two pipes coming into it. one is a 4" (maybe 5") PVC, which I believe is typical of a drain tile system. The other is a similarly sized piece of black flexible pipe (but very thick / sturdy stuff). The oddity is that water comes in through the PVC pipe, but I...