Which Safe Water Drinking Act (SWDA) establishes action levels rather than MCLs?

The Safe Drinking Water Act (SDWA) establishes federal standards to ensure the safety of drinking water. It uses Maximum Contaminant Levels (MCLs) to regulate harmful substances in drinking water. However, for certain contaminants, the Act designates action levels rather than MCLs, which require water systems to take specific actions if the contaminant concentration exceeds a certain threshold.

The Lead and Copper Rule, part of the SDWA, specifically uses action levels to manage these two contaminants because of the health risks they pose, particularly to vulnerable populations such as children. An action level for lead is set at 0.015 mg/L, while for copper, the action level is 1.3 mg/L. If a water system exceeds these levels in more than 10% of samples, it must take actions to reduce the lead and copper levels, such as optimizing corrosion control.

In contrast, the other options refer to contaminants that have established MCLs rather than action levels. Understanding the differences in how regulatory levels are set for various contaminants helps water operators prioritize and manage public health risks effectively.