A leach field form comprising: a container with an open bottom and an open top, and four exterior walls of a first height, and at least one interior wall; at least one geonet volume with an open bottom and an open top located in the container; at least one granular volume with an open bottom and an open top located in the container; and where any of the at least one geonet volumes is separated from any adjacent granular volume by an interior wall. A method of making a leach field using a leach field form comprising: digging a trench; placing a leach field form in the trench; backfilling the trench, allowing backfill to fill any granular volumes in the form; inserting geonet into geonet volume located in the form; and removing the form from the trench.