At the chosen location, begin by digging a pit, either round or square, about 1 meter across, and from 1-3 meters deep. The table below shows recommended depths for a latrine for a family of 5. The same depths may be used for latrines in public buildings such as schools or clinics provided there will be 1 latrine for every 15 people who use the building regularly.
On the table, "wet pit type" refers to pits which penetrate the water table in the ground and are constantly wet. "Dry pit type" refers to pits that are 3 meters or more above the highest underground water level.
If the soil is soft and tends to cave in during the digging, line the pit with stone, brick, wood, or bamboo to keep the sides of the pit strong. Even when the soil is firm, it's a good idea to line the upper few feet.