Sewage is a water-carried waste, in solution or suspension, that is intended to be removed from a community. Also known as wastewater, it is more than 99% water and is characterized by volume or rate of flow, physical condition, chemical and toxic constituents, and the bacteriological organisms that it contains. It consists mostly of greywater (from sinks, tubs, showers, dish and clothes washers, and toilets) and the human waste that the toilets flush away; soaps and detergents; and toilet paper (less so in regions where bidets are widely used instead of paper). Whether it also contains surface runoff depends on the design of its route back to the environment. All sewage ends up back in the environment (from which its constituents came), by any of several routes. A basic distinction in its route is whether it is treated in any way to mitigate its effect on the environment before arriving there. Sewage usually travels from a building's plumbing either into a sewer, which will carry it elsewhere, or into an onsite sewage facility (of which there are many kinds). Whether it is combined with surface runoff in the sewer depends on the sewer design (sanitary sewer or combined sewer). Before the 20th century, sewers usually discharged into a body of water such as a stream, river, lake, bay, or ocean. There was no treatment, so the breakdown of the human waste was left to the ecosystem. Today, the goal is that sewers route their contents to a wastewater treatment plant rather than directly to a body of water. In many countries, this is the norm; in some developing countries, it may be a yet-unrealized goal. In general, with passing decades and centuries, humanity seeks to be smarter about the route of sewage on its way back to the environment, in order to reduce environmental degradation and achieve sustainability. Thus other goals of modern sewage routing include handling surface runoff separately from sewage, handling greywater separately from toilet waste, and coping better with abnormal events (such as peaks in use from internal displacement and peaks in stormwater volumes from extreme weather). In general American English usage, the terms "sewage" and "sewerage" mean the same thing. Both words are descended from Old French assewer, derived from the Latin exaquare, "to drain out (water)". In American technical and professional English usage, "sewerage" refers to the infrastructure that conveys sewage.