That is a link to a very good piece by Ed Glaeser on how zoning regulations impact housing costs in the U.S. and why the "sun belt" states have cheaper places to live. Glaeser's research on zoning laws have revealed patterns to development that transcend some of the shrill political debates. I'm curious about the impact of septic design on the formulation of large lot zoning here in the Northeast. Prior to better regulations on sewage disposal, small houselots were more common--even after the automobile revolution took hold. Large lots, which I'll arbitrarily classify as greater than 20,000 s.f. are often the legal minimum in Boston area suburbs. This affords enough room for an individual septic system. Down south and out west, smaller lot sizes in very large subdivisions (on flat land, usually) depend on municipal water and sewage systems. Developers, who have to help finance the build-out of these systems reap the benefits of economies of scale and also take advantage of the more liberal zoning regulations.