Scientific Background for the Development of Regulations for Radionuclides in Drinking Water

Nearly all of the radionuclides occurring in drinking water supplies are naturally occurring. The radionuclides in drinking water will vary somewhat according to the source of the water. Under the Safe Drinking Water Act, public drinking water supplies are defined as those that serve 25 or more people or have 15 or more service connections. The water for 800Jo of the nation's 60,000 public water supplies comes from ground water sources. Nearly 700Jo of the population is served by the public drinking water supplies that use surface water.