Basic Information about Your Drinking Water

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Water faucet.

The United States enjoys one of the world's most reliable and safest supplies of drinking water. Congress passed the Safe Drinking Water Act (SDWA) in 1974 to protect public health, including by regulating public water systems. 

In 1984 Congress amended the SDWA, including provisions to:

  • Increase the pace of regulation
  • Strengthen enforcement
  • Help protect ground water sources of drinking water

Additional amendments in 1996 expanded the SDWA to protect drinking water comprehensively, including by:

  • Authorizing risk-based standard-setting for contaminants that may affect public health
  • Requiring that water systems inform consumers about contaminants in their drinking water and violations of the law
  • Creating a multi-billion dollar loan fund for drinking water infrastructure
  • Establishing programs to address challenges faced by small water systems
  • Promoting the protection of surface and ground water sources of drinking water from contamination

EPA and the states administer the SDWA’s programs.  Explore this site for information about the Safe Drinking Water Act and its programs.

Drinking water may come from surface water or ground water. Water that is open to the atmosphere, such as rivers, lakes, and reservoirs, is known as surface water.  Surface water typically undergoes a series of treatment processes before being piped through distribution systems to homes, schools, and businesses.

Water pumped from wells drilled into underground aquifers (geologic formations containing water) is called ground water.  Over a third of people in the United States rely on ground water from public water systems or private wells.

Over 150,000 public water systems provide drinking water to most Americans. A public water system has at least 15 service connections or serves 25 or more people regularly during the year.  Public water systems may be publicly or privately owned.

Public water systems are regulated under the SDWA. These systems must ensure that the water they provide meets health standards established in EPA regulations. They must also test the water according to schedules in the regulations.

About 10 percent of people in the United States rely on water from private wells. Private wells are not regulated under the SDWA.  People who use private wells need themselves to take precautions to ensure their drinking water is safe.

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