Carol, actually, we are above the flood plain, and I dont think we need more than one tank (since it is not a full time residential house). $10.5K? Ouch! We were hoping to do much of the installation ourselves to save $$$. Thanks for the reply. You wouldnt have any clue what a basic system would cost? 500 gallon tank with a leach field (minus the excavation)? Basically I need to know how much the materials are, and where I can find them… I really appreciate the response! Thanks again…