There are approximately 153,530 public drinking water systems in the United States. Each of these systems regularly supplies drinking water to at least 25 people or 15 service connections. Beyond their common purpose, these systems vary widely. The following tables group water systems into categories that show their similarities and differences. For example, the first table shows that most people in the US (294 million) get their water from a community water system. There are approximately 52,000 community water systems, but just eight percent of those systems (4,132) serve 82 percent of the population. The second table shows that more water systems have ground water than surface water as a source - but more people drink from a surface water system. Other tables break down these national numbers by state, territory, and EPA region. This package also contains figures on the types and locations of underground injection control wells. EPA and the States regulate the placement and operation of these wells to ensure that they do not threaten underground sources of drinking water. The underground injection control program statistics are based on separate reporting from the States to EPA.