A pit latrine or pit toilet is a type of toilet that collects human feces in a hole in the ground. They use either no water or one to three liters per flush with pour-flush pit latrines. When properly built and maintained they can decrease the spread of disease by reducing the amount of human feces in the environment from open defecation. This decreases the transfer of pathogens between feces and food by flies. These pathogens are major causes of infectious diarrhea and intestinal worm infections. Infectious diarrhea resulted in about 0.7 million deaths in children under five years old in 2011 and 250 million lost school days. Pit latrines are the lowest cost method of separating feces from people.
A pit latrine generally consists of three major parts: a hole in the ground, a slab or floor with a small hole, and a shelter. The pit is typically at least 3 meters (10 feet) deep and 1 m (3.2 feet) across. The World Health Organization recommends they be built a reasonable distance from the house balancing issues of easy access versus that of smell. The distance from groundwater and surface water should be as large as possible to decrease the risk of pollution. The hole in the slab should not be larger than 25 centimeters (9.8 inches) to prevent children falling in. Light should be prevented from entering the pit to reduce access by flies. This may require the use of a lid to cover the hole in the floor when not in use. When the pit fills to within 0.5 meters (1.6 feet) of the top, it should be either emptied or a new pit constructed and the shelter moved or re-built at the new location. The management of the fecal sludge removed from the pit is complicated. There are both environment and health risks if not done properly.
A basic pit latrine can be improved in a number of ways. One includes adding a ventilation pipe from the pit to above the structure. This improves airflow and decreases the smell of the toilet. It also can reduce flies when the top of the pipe is covered with mesh (usually made out of fiberglass). In these types of toilets a lid need not be used to cover the hole in the floor. Other possible improvements include a floor constructed so fluid drains into the hole and a reinforcement of the upper part of the pit with bricks or cement rings to improve stability.
As of 2013 pit latrines are used by an estimated 1.77 billion people. This is mostly in the developing world as well as in rural and wilderness areas. In 2011 about 2.5 billion people did not have access to a proper toilet and one billion resort to open defecation in their surroundings. Southern Asia and Sub-Saharan Africa have the poorest access to toilets. In developing countries the cost of a simple pit toilet is typically between 25 and 60 USD. Ongoing maintenance costs are between 1.5 and 4 USD per person per year which are often not taken into consideration. In some parts of rural India the "No Toilet, No Bride" campaign has been used to promote toilets by encouraging women to refuse to marry a man who does not own a toilet.