There are many differences between deep geothermal wells and domestic water boreholes. Deep geothermal wells are cased in steel and cement from the surface for approximately ¾ of their depth and bring geothermal fluid contained in fractures at 4,000-5,000m depth to the surface. After the hot fluid has been used to produce renewable electricity, the water is reinjected underground to approximately 2,500m depth. In comparison, domestic water boreholes are rarely more than 200m deep and are cased with either steel or plastic with either an open hole section or perforated cased section in the part of the rock which contains the fresh water. The water from domestic boreholes is not deposited back underground, therefore the water extracted from a borehole is not replenished by the borehole user