This toilet consists of two pits, each covered with a slab with a drop hole and a vent pipe covered with a fly screen, and one superstructure. (see figure 2). The drop hole must remain open, because closing it blocks airflow. The door should be closed so the superstructure remains dark inside. Only one pit is used at a time. When the first pit's contents rise to 0.5 meter below the slab, its drop hole is covered and the second pit is used. After a period of at least one year, the contents of the first pit can be removed safely and used as soil conditioner.

Twin-pits for pour-flush toilets are two underground leaching pits linked to one single pour-flush toilet by a Y-junction. The two pits are used alternately. Blackwater (i.e. excreta, flushing water and anal cleansing water) is directed into one of the pits. The pits are lined either with a porous material or holes in the walls allowing the liquid to infiltrate into the surrounding soil. During soil infiltration, most of the pathogens are filtered or die-off with time and distance - but in densely populated areas, it can still lead to the pollution of ground water.

The safe disposal of human waste (sanitation) by building and maintaining toilets and washing hands prevents the spread of germs and is necessary for good health. This Chapter 7 “Building Toilets”, has been taken from the resource book - A Community Guide to Environmental Health, published in 2008 by the Hesperian Foundation, is a manual that looks at the various aspects of sanitation and toilet building, including understanding sanitation needs of different groups (men, women, children, disabled), planning for toilets for rural areas, cities/towns and emergencies and looks at the various toilet options available and methods to set up each one of them.
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