Groundwater is a major national resource. In Britain, 20 times more water is stored in underground aquifers than in surface water reservoirs and lakes. Groundwater provides three-quarters of public water supplies in South-East England and 35% of supplies in England as a whole. In Scotland for example, there are around 30,000 private groundwater sources, many supplying individual properties. Groundwater is used to irrigate crops and water livestock, as well as provide drinking water for humans.