A toilet is a piece of sanitary hardware used for the collection or disposal of human urine and feces. Toilets can be with or without flushing water. They can be set up for a sitting posture or for a squatting posture. Flush toilets are usually connected to a sewer system in urban areas and to septic tanks in isolated areas. Dry toilets are connected to a pit, removable container, composting chamber, or other storage and treatment device. Toilets are commonly made of ceramic (porcelain), concrete, plastic, or wood.