The General Organization for Greater Cairo Water Supply (GOGCWS) is responsible for the supply of potable water and untreated industrial and irrigation water to the residents and industries of Greater Cairo, Egypt's capital and largest city. The water is produced at 12 filtration plants using Nile water and three well fields. GOGCWS employs 12,000 persons in a range of technical and administrative fields and serves a population of more than 14 million people in an area of about 400 square kilometers. Since nationalization in 1956, the organization has undergone several reorganizations, in 1964, 1968, and 1973.