Looking at Land

While I haven't posted for a while, I have looked at several pieces of land. One of them in particular has my attention because it is in the perfect location for me and my wife, and has a very low price tag. The cheap price is probably due to a substantial slope in the land down from the road. A real topographical study hasn't been done, but I sketched out some rough lines indicating the terrain:I know that building on a slope can provide some serious challenges, but I think it could provide some unique opportunities as well. I really like the feel of sloping terrain, and I think the fact that the general slope is down toward the south could be advantageous for the passive solar/earth sheltered design that I'm thinking about.

My concerns are that excavation cost would be high, and that the property feels like it is sloping in the bottom of a "valley" and might not receive as much sun as I desire. Here's a close up from Microsoft's Virtual Earth:


The lot is approx 1.75 acres, and is approved with perk tests complete.

Does anybody have precautions I should investigate regarding building on a steep slope, or selecting a piece of land in general?