Historically, this process was know as a “Perc Test”, which simply involved digging a hole, filling it with water, and measuring how long it took to drain away. Over time, perc tests proved to be unreliable in predicting the long term ability of soil to accept sewage effluent and were subsequently phased out of code beginning in 1992.
Now a “Soil Morphological Evaluation” (soil test) is completed which requires that the soil tester excavate a series of backhoe pits surrounding the proposed septic system area. The Soil Tester then takes a “worms eye view” of the soil, determining the texture and structure of the soil from the ground surface down to a minimum depth of 3′ below the proposed system infiltrative surface. Engineering standards are then applied which specify how much water can be put into one square foot of the native soil.
A thorough Soil & Site Evaluation will take several things into consideration, including landscape position, slopes, topography, soil type, existing and proposed landscaping and construction considerations, all while taking into account the future needs of the property owner.
The most efficient location for the proposed septic system is then chosen and the soil is evaluated to be certain that a system can be placed at that location. If the soil proves to be unsuitable, the process is started over and continues until the most suitable site is found.
The final step in the process is to complete a report that indicates the location, type, size and elevation of the septic system as well as any unique design considerations that may be required. The report is submitted for review and filing with the County Agency responsible for administering the Sate’s Sanitary Codes.