"13Things You Need To Know Before You Buy a Lot?"

Ontario Home Builder
Rule #1: Don’t Build on Fill:
Your foundation needs to rest on solid, undisturbed ground. It can take hundreds of years for ground to settle.
Sometimes, a steep ravine may have been filled in and/or the land may have previously been a dump.
If you cannot dig down far enough to rest the footings on solid and undisturbed ground, then you run the risk of having the ground settle after you home is built. More: http://www.ontario-home-builder.com/Normal-House-Builder.htm