Gelsenwasser AG engages in the water, wastewater, gas supply, and electricity businesses in Germany, the Czech Republic, and Poland. The company operates through Water, Wastewater, Energy Networks, Energy Procurement and Distribution, and Investments and Projects segments. It also engages in the purchase, production, sale, and transport and distribution of drinking water. In addition, the company is involved in the wastewater related business, which include water supply, wastewater disposal, and groundwater management activities, as well as engages in the gas and electricity network activities. Further, it is involved in the purchase and sale of natural gas, electricity, and heat to household customers, special contract customers, and resellers; and the energy procurement and trading business; and invests primarily in municipal utilities. The company was formerly known as Wasserwerk für das nördliche westfälische Kohlenrevier and changed its name to Gelsenwasser AG in 1973. Gelsenwasser AG was founded in 1887 and is based in Gelsenkirchen, Germany. The company operates as a subsidiary of Wasser und Gas Westfalen GmbH & Co. Holding KG.