Abstract: A prefabricated panel section formed of a strong, porous material and having a plurality of longitudinally extending, preferably vertically spaced chambers or compartments therein throughout the length of the section. A first pipe from a septic tank or preceding similar panel section has an outlet end opening directly into the uppermost chamber. A second pipe, conduit or other opening extends downwardly through the webs which separate the chambers to provide access to and egress from each compartment for air, chemicals, and effluent. In a preferred embodiment the top wall of the panel section or a portion is fabricated as a removable cover through which access to the system is gained. The panels may be grouped and connected together to form a complete ground absorption or percolation system.