As an owner-builder septic laws are some of my most despised government interventions. In PA the laws are some of the most deplorable in the country. They are not based on science, they are not flexible, and they make for a very expensive system. As a main principle of building my own place, I don't have a morgage but I am paying down a loan for my mound system.
Here is the homepage for some folks in Mass. who have a better idea. You will notice, however, that the state is now on the case, saving the neighbors from all those awful flowers they are growing where there should be a mound system.