Drinking water quality in the United States

Drinking water quality in the United States is generally safe. In 2016, over 90 percent of the nation's community water systems were in compliance with all published U.S. Environmental Protection Agency (US EPA) standards.[1] Over 286 million Americans get their tap water from a community water system. Eight percent of the community water systems—large municipal water systems—provide water to 82 percent of the US population.[2] The Safe Drinking Water Act requires the US EPA to set standards for drinking water quality in public water systems (entities that provide water for human consumption to at least 25 people for at least 60 days a year).[3] Enforcement of the standards is mostly carried out by state health agencies.[4] States may set standards that are more stringent than the federal standards.[5]

Despite improvements in water quality regulations, disparities in access to clean drinking water persist in marginalized communities. A 2017 study by the Natural Resources Defense Council (NRDC) highlighted that rural areas and low-income neighborhoods are disproportionately affected by water contamination, often due to aging infrastructure and inadequate funding for water systems.[6] These inequities underscore the need for more targeted investment and stronger enforcement of the Safe Drinking Water Act in vulnerable regions.


Drinking water quality in the U.S. is regulated by state and federal laws and codes, which set maximum contaminant levels (MCLs) and Treatment Technique requirements for some pollutants and naturally occurring constituents, determine various operational requirements, require public notification for violation of standards, provide guidance to state primacy agencies, and require utilities to publish Consumer Confidence Reports.[7]

EPA has set standards for over 90 contaminants organized into six groups: microorganisms, disinfectants, disinfection byproducts, inorganic chemicals, organic chemicals and radionuclides.[8] EPA also identifies and lists unregulated contaminants which may require regulation. The Contaminant Candidate List is published every five years, and EPA is required to decide whether to regulate at least five or more listed contaminants.[9] There are also many chemicals and substances for which there are no regulatory standards applicable to drinking water utilities. EPA operates an ongoing research program to analyze various substances and consider whether additional standards are needed.[10]

Most of the public water systems (PWS) that are out of compliance are small systems in rural areas and small towns. For example, in 2015, 9% of water systems (21 million people) were reported as having water quality violations and therefore were at risk of drinking contaminated water that did not meet water quality standards.[11][full citation needed]

  1. ^ Beauvais, Joel (April 26, 2016). "Moving Forward for America's Drinking Water". EPA Blog. Washington, D.C.: U.S. Environmental Protection Agency (EPA). Archived from the original on May 25, 2017. Retrieved December 17, 2017.
  2. ^ "Public Water Systems". Atlanta, GA: U.S. Centers for Disease Control and Prevention (CDC). April 7, 2014.
  3. ^ United States. Safe Drinking Water Act. Pub. L. 93–523; 88 Stat. 1660; 42 U.S.C. § 300f et seq. 1974-12-16.
  4. ^ "Primacy Enforcement Responsibility for Public Water Systems". Drinking Water Requirements for States and Public Water Systems. Washington, D.C.: United States Environmental Protection Agency (EPA). 2016-11-02.
  5. ^ Understanding the Safe Drinking Water Act (Report). EPA. June 2004. EPA 816-F-04-030.
  6. ^ "Threats on Tap: Widespread Violations Highlight Need for Investment in Water Infrastructure and Protections". Natural Resources Defense Council. April 2017. Retrieved October 5, 2024.
  7. ^ Joseph Cotruvo, Victor Kimm, Arden Calvert. "Drinking Water: A Half Century of Progress." EPA Alumni Association. March 1, 2016.
  8. ^ "National Primary Drinking Water Regulations". Ground Water and Drinking Water. EPA. 2019-09-17.
  9. ^ "Basic Information on the CCL and Regulatory Determination". Contaminant Candidate List. EPA. 2019-07-19.
  10. ^ "Basic Information on the CCL and Regulatory Determination". Contaminant Candidate List (CCL). EPA. 2022-03-21.
  11. ^ Condon, Madison. "Rural America's Drinking Water Crisis". ABA. Archived from the original on 2020-09-22. Retrieved 2021-04-01.{{cite web}}: CS1 maint: bot: original URL status unknown (link)