A LPD and Gravity drainfield consist of trenches that are filled with Infiltrators. The number of trenches depends on what the design flows are and the soil type. A gravity system typically has 3 or more trenches that are fed by a distribution box (dbox). A drip system does not use trenches and had tubing instead, they a usually only 6" deep. Please refer to the "Systems We Install" under the "Services" tab for more details pertaining to each type of septic system.