Septic Tanks Septic tanks are one of those things that we want to be out of sight and out of mind, but the state of Maryland has recently passed legislation that has brought septic tanks to the forefront. The impetus for the new law is to improve the water quality of the Chesapeake Bay, a most worthy cause that we all want to support. That’s the good news. The bad news is that these high tech septic tanks add about $10,000 to the cost of a typical septic system, not including typical yearly maintenance costs. And while we can all.