A Septic tank system Access manhole Access House manhole//Leaching Inle Outlet sewer field line Septic Distribution tank box Perforated Sludge (a)Overall plan. Most soluble organic matter is (b)A section of a septic tank disposed of by percolation into the soil Copyright @2001 Benjamin Cummings, an imprint of Addison Wesley Longman, IncA Septic Tank System