Two contractors have told me contracdictory things about how deep my new house's basement could/should be set in the ground.
The site is on a gentle hill top, so water running toward the house should not run directly into the basement. The contractor who dug the cellar hole and put in the foundation said the the basement could not be sunk into the ground the amount originally planned (i.e., so only its top would be 12"-18" about the old ground level. He claimed we would have water in the basement frequently. So he sank it 3'-4' less and used the spoils from the cellar hole to make a mound around the house except where the garage goes. There is a 1/3 flight of stairs down to the garage floor level.
Another contractor told us the first was wrong. The house plans included a layer of several feet of rock under the basement and a drain pipe running out to the driveway down hill of the house. He said that should be adequate.