The Safe Drinking Water Act (SDWA) requires EPA to review each National Primary Drinking Water Regulation (NPDWR) at least once every six years and revise them, if appropriate. The purpose of the review, called the Six-Year Review, is to identify those NPDWRs for which current health effects assessments, changes in technology, and/or other factors provide a health or technical basis to support a regulatory revision that will maintain or strengthen public health protection. To support the national contaminant occurrence and exposure assessments performed under the Six-Year Review process, EPA analyzes SDWA compliance monitoring data from public water supplies for regulated drinking water contaminants. This analysis allows EPA to characterize the national occurrence of contaminants to help the Agency determine if there may be a meaningful opportunity to improve public health protection.

In December 2016, EPA announced the review results for the Agency’s third Six-Year Review (called Six-Year Review 3). EPA analyzed compliance monitoring data for the Six-Year Review 3 using data provided by states/primacy agencies through the Information Collection Request (ICR) for Six-Year Review 3 covering January 2006 through December 2011. Each zip file contains data for multiple contaminants and related information that can be unzipped into tab delimited text files. The number of records and associated systems in the data files and the size of the files range considerably from contaminant to contaminant, which may be attributed to many factors such as the applicability of monitoring requirements, the required sampling frequency and results from quality assurance/quality control (QA/QC) measures. A detailed description of the data fields and their definitions, notes about the data, and instructions for downloading and importing datasets into software applications such as Excel can be found in the User Guide. Citation information for this dataset can be found in Data.gov's References section.

In December 2016, EPA announced the review results for the Agency’s third Six-Year Review (called Six-Year Review 3). EPA analyzed compliance monitoring data for the Six-Year Review 3 using data provided by states/primacy agencies through the Information Collection Request (ICR) for Six-Year Review 3 covering January 2006 through December 2011. Each zip file contains data for multiple contaminants and related information that can be unzipped into tab delimited text files. The number of records and associated systems in the data files and the size of the files range considerably from contaminant to contaminant, which may be attributed to many factors such as the applicability of monitoring requirements, the required sampling frequency and results from quality assurance/quality control (QA/QC) measures. A detailed description of the data fields and their definitions, notes about the data, and instructions for downloading and importing datasets into software applications such as Excel can be found in the User Guide. Citation information for this dataset can be found in Data.gov's References section.

EPA uses the Unregulated Contaminant Monitoring (UCM) program to collect data for contaminants suspected to be present in drinking water, but that do not have health-based standards set under the Safe Drinking Water Act (SDWA). Every five years EPA reviews the list of contaminants, largely based on the Contaminant Candidate List.

EPA uses the Unregulated Contaminant Monitoring (UCM) program to collect data for contaminants suspected to be present in drinking water, but that do not have health-based standards set under the Safe Drinking Water Act (SDWA). Every five years EPA reviews the list of contaminants, largely based on the Contaminant Candidate List.

National Primary Drinking Water Regulations (NPDWRs or primary standards) are legally enforceable standards that apply to public water systems. Primary standards protect public health by limiting the levels of contaminants in drinking water.

National Primary Drinking Water Regulations (NPDWRs or primary standards) are legally enforceable standards that apply to public water systems. Primary standards protect public health by limiting the levels of contaminants in drinking water.

A database where EPA has compiled data on public drinking water systems and whether they have certain drinking water violations. This data is collected by the states and given to the EPA. This dataset is associated with the following publication: Pennino, M., J. Compton, and S. Leibowitz. Trends in Drinking Water Nitrate Violations Across the United States. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, USA, 13450-13460, (2017).

SDWIS/State is a data system that EPA is developing for states that will improve the quality of drinking water information.

SDWIS/FED is EPA's national regulatory compliance database for the drinking water program. It includes information on the nation's 160,000 public water systems and violations of drinking water regulations. Access aggregated information on all violations reported in an EPA region, state, and county since 1993 using the MS Excel PivotTables. These multidimensional tables contain aggregated information on water systems; violations reported by violation type and by contaminant/rule, and GPRA data, for each year since 1993; and current Envirofacts data. Sort, categorize, and analyze the data across several dimensions.