A composting toilet is a type of dry toilet that uses a predominantly aerobic processing system to treat human excreta, by composting or managed aerobic decomposition. These toilets generally use little to no water and may be used as an alternative to flush toilets. They have found use in situations where no suitable water supply or sewer system and sewage treatment plant is available to capture the nutrients in human excreta. They are in use in many roadside facilities and national parks in Sweden, Canada, US, UK and Australia. They are used in rural holiday homes in Sweden and Finland.

A dry toilet is a toilet that operates without flush water, unlike a flush toilet. The dry toilet may be a raised pedestal on which the user can sit, or a squat pan over which the user squats in the case of a squat toilet. In both cases, the excreta (both urine and feces) falls through a drop hole. The urine and feces can either become mixed at the point of dropping or stay separated, which is called urine diversion.