Glenn Herbert wrote:It seems the building site itself is flat, and the slope for drainage is 100' or so away. I just think it is a bad idea to intentionally depend on an electrical appliance to ensure the house will never flood.
You want your house underground... do you mean completely surrounded by dirt with a green roof? Or fully bermed with a metal roof that can serve for water collection? A point to remember is that you don't need to dig down 6' to have fully earth-covered walls. If you dig 8' x 16' x 3' deep, you will have enough dirt dug up to berm three sides another 4' up, or 7' total walls, which is plenty for a one-person dwelling. Roof slope will make most of the space considerably taller. In your situation, I would make the bermed walls maybe 6' tall, with decent roof slopes making the high point(s) something like 9' or 10'. Digging for a sunken porch or a greenhouse on the south side will increase the available berm material with even less digging down.