A Percolation Test and Site Assessment is essentially an analysis of your proposed site, the permeability qualities of the soil and the height of the water table on the proposed site. This test is done in order to determine what type of wastewater treatment system or septic tank and percolation area would be most suitable to deal with the household wastewater on your proposed site.
A percolation (permeability) test assesses the hydraulic assimilation capacity of the subsoil i.e. the length of time for the water level in the percolation hole to drop by a specified amount. The objective of the percolation test is to determine the ability of the subsoil to hydraulically transmit the treated effluent from the treatment system, through the subsoil to groundwater. The test also gives an indication of the likely residence time of the treated effluent in the upper subsoil layers and therefore it provides an indication of the ability of the subsoil to treat the residual pollutants contained in the treated effluent.