We recommend at least 1/2 of an acre of flat land for every 4000 square feet of livable space. Not including garage space. So, for a 7000 square foot home we recommend at least an acre of flat land. For a hill side lot we like 1/2 acre for every 3000 square feet. The Best lots to build on, are square which gives you the best options. We also like rectangle lots that the wide side faces towards the street.