Water supplies meeting treatment requirements

GOAL: Meet treatment requirements / METRIC: Water supplies meeting treatment requirements

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What we track

Blue Accounting is tracking the percentage of water supplies in the Great Lakes basin that meet treatment requirements as water leaves the treatment plant.

Water treatment around the Great Lakes basin

Prior to distribution to water customers, sources of drinking water are treated to ensure that high quality water is delivered from treatment plants, which may be owned by local governments or private businesses. Blue Accounting’s Drinking Water issue is focused on water supplies serving the public, which are known as community water supplies in the United States and municipal water supplies in Canada. These water supplies treat water extracted from a source, including one of the Great Lakes, an inland waterbody, or groundwater.

Similar assessments conducted under the Great Lakes Water Quality Agreement more narrowly examine the population served by community water systems meeting all health-based standards for the U.S. For Ontario, the assessment examines treated water sample results in compliance with water quality standards.

Blue Accounting is examining health-based standard violations, while adding acute health-based monitoring and reporting and public notification categories of violations. This provides a more detailed picture that informs state and provincial agencies, the federal government, and ultimately drinking water customers of new or emerging issues with water treatment at the 4,489 community water systems in the Great Lakes basin.

Currently the Explore tab dashboard presents U.S. data only. Data from the Canadian provinces is pending.

Why it matters

Treatment requirements are carefully established by federal, state, and provincial governments to protect public health.

State of the Great Lakes 2022 report with additional input provided by members of the Drinking Water work group (December 2022).

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What do the violation categories include?

  • Health-Based Violations: Violations of maximum contaminant levels (MCLs) or maximum residual disinfectant levels (MRDLs), which specify the highest concentrations of contaminants or disinfectants, respectively, allowed in drinking water; or of treatment technique (TT) rules, which specify required processes intended to reduce the amounts of contaminants in drinking water.
  • Acute Health-Based Violations: Health-based violations that have the potential to produce immediate illness. EPA specifically defines these as maximum contaminant level (MCL) violations where the regulated contaminant is either total coliform or nitrate.
  • Monitoring and Reporting (MR) Violations: Failure to conduct regular monitoring of drinking water quality, as required by SDWA, or to submit monitoring results in a timely fashion to the state environmental agency or EPA.
  • Public Notice (PN) Violations: Violations of the SDWA public notification requirements to immediately alert consumers if there is a serious problem with their drinking water that may pose a risk to public health.
  • Other Violations: Violations of other requirements of SDWA, such as issuing annual consumer confidence reports, or conducting periodic sanitary surveys.

Because the focus of this dashboard is on issues with water treatment, it does not include violations of the Lead and Copper Rule related to post-treatment problems in the distribution system.

EPA ECHO Drinking Water Dashboard with additional input provided by members of the Drinking Water work group (December 2022).

This bar chart shows a subset of the EPA SDWIS dataset used in the Explore tab that is focused on health-based violations of EPA drinking water treatment rules, broken out into specific contaminant types identified by the Drinking Water work group. Hover over a bar to see numbers of violations, click contaminant types in the legend to turn them on/off, or use the dropdown to filter by jurisdiction.

Certain contaminants of emerging concern, such as PFAS and algal toxins, are not yet federally regulated and monitored in the U.S. under the Safe Drinking water Act and therefore do not appear in the bar chart below. The U.S. EPA and Health Canada are in the process of developing proposed regulations and MCLs for some PFAS chemicals.

Learn more about the sources of key contaminants, their contamination standards, and how drinking water is treated to meet SDWA standards by clicking on each link below the chart.

Selection of contaminants determined through input provided by members of the Drinking Water work group (December 2022).