Basic drinking water is defined as a functional improved drinking water source on or near the premises and water points accessible to all users during school hours. An improved drinking water source is a water delivery point that by the nature of its design protects the water from external contamination, particularly of fecal origin. Examples of improved drinking water facilities include piped water, protected wells, tubewells and boreholes, protected springs and rainwater, purchased bottled water and tanker-trucks. Unimproved water sources include unprotected wells and springs and surface water (e.g. rivers, lakes).
UNESCO Institute for Statistics.