Drainfield trenches should be installed level and on the contour. If surfacing occurs at the end of one or more trenches, they should be checked to see that they are level. A trench sloping away from a dropbox or the distribution box may result in effluent surfacing rather than going on to the next trench. Depth to the top of the drainfield media should be measured to determine if the trench is level and on the contour. Solutions may require replacing the trenches or, depending on slope and location, adding fill while staying within code requirements.
If effluent is surfacing in
