Safe Drinking Water Act Compliance Monitoring
Providing safe drinking water relies on the partnership between EPA and states, territories, and Tribes with EPA approval to implement the Safe Drinking Water Act or SDWA. Working with their public water systems and their operators, and certified laboratories that conduct required analyses of drinking water samples, EPA and its partners monitor compliance under the following SDWA regulatory requirements.
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Public Water Systems
Public water systems must meet health-based federal standards for contaminants, including performing regular monitoring and reporting.
The Public Water System Supervision or PWSS program is designed to protect public health by ensuring the safety of drinking water. Public water systems are regulated by EPA, and primacy agencies (states, territories, and Tribes with EPA approval to implement the SDWA) and provide drinking water to 90% of the public. These public drinking water systems, which may be publicly- or privately-owned, serve at least 15 service connections or 25 persons. Private, individual household wells are not regulated by EPA.
EPA and primacy agencies monitor public water system compliance with the SDWA and its implementing regulations by reviewing and evaluating analytical results of water samples collected and reported by public water systems. These reports provide the public water systems and regulators with the data needed to ensure drinking water monitoring is ongoing and drinking water standards are being met. When results indicate that a contaminant is present at a level that exceeds standards, primacy agencies and EPA work with public water systems to take steps to prevent or remove the contaminants and notify consumers so that they can make informed choices.
The America’s Water Infrastructure Act of 2018 amended section 1433 of the SDWA to require community water systems, a public water system that supplies water to the same population year-round and serves more than 3,300 people, to complete a risk and resilience assessment and develop an emergency response plan or ERP.
Risk and resilience assessments include an evaluation of risk to community water systems from malevolent acts, including cyberattacks, and natural hazards. A community water system must prepare or revise an ERP that incorporates the findings of the risk and resilience assessment. Given vulnerabilities and attacks on these systems, EPA is increasing the number of community water system inspections that focus on cybersecurity. More information on EPA’s work to combat cyberattacks is available from EPA Increases Enforcement Activities to Ensure Drinking Water Systems Address Cybersecurity Threats.
Underground Injection Control
Underground injection is the technology of placing fluids underground into porous formations of rocks through wells or similar conveyance systems. The Underground Injection Control or UIC program regulates the construction, operation, permitting, and closure of injection wells. It is designed to ensure that underground injection wells do not endanger any current and future underground sources of drinking water. EPA's and states' primary means of monitoring UIC compliance with SDWA regulations is to inspect the regulatory permit conditions on-site at UIC facilities.
EPA’s underground injection control program information web page for the types and purposes of injection wells and for guidance on injection well construction and operation to prevent contamination of underground drinking water resources.