Safe Drinking Water Act (SWDA) (College Board AP® Environmental Science): Study Guide

Safe Drinking Water Act (SDWA)

Background

• Developed in response to widespread concerns about contamination in public water supplies

  • In the mid-20th century, industrial and agricultural pollutants like lead, nitrates, arsenic, and microbial pathogens were increasingly found in drinking water

  • There was no uniform standard for water quality at the federal level

• The SDWA was enacted to:

  • Ensure safe drinking water for the public

  • Regulate any public water system that serves more than 25 people

  • Protect water from source to tap, including rivers, lakes, reservoirs, and groundwater supplies

Key Dates

• 1974: Safe Drinking Water Act passed

• 1986 & 1996: Major amendments expanded protection to underground sources, added pollutant monitoring, and increased public access to water quality information

How the Safe Drinking Water Act relates to the environment

• Authorizes the Environmental Protection Agency (EPA) to set National Primary Drinking Water Regulations (NPDWRs)

  • These standards limit the levels of contaminants like lead, arsenic, nitrates, and microbes in drinking water

  • Water suppliers must regularly test water and report violations

• The SDWA protects both surface water and aquifers used for public water supplies

Evaluation

• Successes:

  • Over 90 contaminants are now monitored and regulated under the SDWA

  • Vast improvements in the safety of public water systems across the U.S.

  • Empowers communities to demand accountability through public reporting of water quality

  • Reduced outbreaks of waterborne diseases like giardiasis and cholera

• Challenges:

  • Lead contamination (e.g. Flint, Michigan) shows the uneven enforcement of standards and oversight failures

  • Many aging water systems (pipes, treatment plants) need costly upgrades

  • New emerging contaminants (e.g. PFAS, microplastics) are not yet regulated under current SDWA rules

  • Small or rural water systems may lack funding or infrastructure to comply with all requirements