Squat toilet in the context of "Toilet seat"

A toilet is a piece of sanitary hardware that collects human waste (urine and feces) and sometimes toilet paper, usually for disposal. Flush toilets use water, while dry or non-flush toilets do not. They can be designed for a sitting position popular in Europe and North America with a toilet seat, with additional considerations for those with disabilities, or for a squatting posture more popular in Asia, known as a squat toilet. In urban areas, flush toilets are usually connected to a sewer system; in isolated areas, to a septic tank. The waste is known as blackwater and the combined effluent, including other sources, is sewage. Dry toilets are connected to a pit, removable container, composting chamber, or other storage and treatment device, including urine diversion with a urine-diverting toilet. "Toilet" or "toilets" is also widely used for rooms containing only one or more toilets and hand-basins. Lavatory is an older word for toilet.

The technology used for modern toilets varies. Toilets are commonly made of ceramic (porcelain), concrete, plastic, or wood. Newer toilet technologies include dual flushing, low flushing, toilet seat warming, self-cleaning, female urinals and waterless urinals. Japan is known for its toilet technology. Airplane toilets are specially designed to operate in the air. The need to maintain anal hygiene post-defecation is universally recognized and toilet paper (often held by a toilet roll holder), which may also be used to wipe the vulva after urination, is widely used (as well as bidets).

A pit latrine, also known as pit toilet, is a type of toilet that collects human waste in a hole in the ground. Urine and feces enter the pit through a drop hole in the floor, which might be connected to a toilet seat or squatting pan for user comfort. Pit latrines can be built to function without water (dry toilet) or they can have a water seal (pour-flush pit latrine). When properly built and maintained, pit latrines 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 700,000 deaths in children under five years old in 2011 and 250 million lost school days. Pit latrines are a low-cost method of separating feces from people.

A pit latrine generally consists of three major parts: a hole in the ground, a concrete slab or floor with a small hole, and a shelter. The shelter is also called an outhouse. The pit is typically at least three meters (10 ft) deep and one meter (3 ft) across. The hole in the slab should not be larger than 25 cm (10 in) 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. The World Health Organization recommends that pits be built a reasonable distance from the house, ideally balancing easy access against smell. The distance from water wells and surface water should be at least 10 m (30 ft) to decrease the risk of groundwater pollution. When the pit fills to within 0.5 m (1+1⁄2 ft) of the top, it should be either emptied or a new pit constructed and the shelter moved or re-built at the new location. Fecal sludge management involves emptying pits as well as transporting, treating and using the collected fecal sludge. If this is not carried out properly, water pollution and public health risks can occur.

A flush toilet (also known as a flushing toilet, water closet (WC); see also toilet names) is a toilet that disposes of human waste (i.e., urine and feces) by collecting it in a bowl and then using the force of water to channel it ("flush" it) through a drainpipe to another location for treatment, either nearby or at a communal facility. Flush toilets can be designed for sitting or squatting (often regionally differentiated). Most modern sewage treatment systems are also designed to process specially designed toilet paper, and there is increasing interest for flushable wet wipes. Porcelain (sometimes with vitreous china) is a popular material for these toilets, although public or institutional ones may be made of metal or other materials.

Flush toilets are a type of plumbing fixture, and usually incorporate a bend called a trap (S-, U-, J-, or P-shaped) that causes water to collect in the toilet bowl – to hold the waste and act as a seal against noxious sewer gases. Urban and suburban flush toilets are connected to a sewerage system that conveys wastewater to a sewage treatment plant; rurally, a septic tank or composting system is mostly used.