A drain field assembly includes a distribution pipe for receiving liquid effluent that has a plurality of holes through the wall. A plurality of generally cylindrical void pipes receive effluent from the distribution pipe, retaining the effluent for a time, and distributing the effluent to an area of soil. The void pipes are positioned in a trench atop one another so that the cylindrical axis of a bottom void pipe is substantially vertically aligned with the cylindrical axis of a top void pipe, and the cylindrical axis of a middle void pipe is offset from those of the bottom and top void pipes. A distribution pipe is positioned within the top void pipe. In some embodiments a second distribution pipe can be positioned atop the top void pipe. A protective soil-impervious, liquid-permeable sheeting is placed atop and beneath the assembly for protecting the holes pipes from intrusion by soil.