The modern toilets; Toilets or toilets use a cistern to reserve and maintain the amount of water required to clean the bowl. initially; the cistern was situated high up; located close to the ceiling; and connected to the bowl by a pipe. it was necessary to pull a chain connected to a valve located inside the cistern; to clean the toilet. modern toilets are conceived as compact units; with the cistern attached to the bowl; the pipe connecting the cistern to the toilet having been removed. concealed cisterns are also available; where the cistern is placed inside the wall behind the toilet. floor plans - sections - structural development and construction details with technical specifications. autocad-dwg.