Where are the maximum contaminant levels for water quality indicators specified?

The maximum contaminant levels for water quality indicators are specifically outlined in the National Primary Drinking Water Regulations (NPDWRs). These regulations are established by the Environmental Protection Agency (EPA) under the authority of the Safe Drinking Water Act. The NPDWRs are designed to protect public health by regulating the levels of contaminants in drinking water systems, ensuring the water is safe for consumption.

The regulations set enforceable limits for various contaminants, which are based on health effects and the feasibility of treatment technologies. This establishes a clear legal framework for water quality standards that must be followed by public water systems. Other sources, such as state health department regulations or guidance from the World Health Organization, may provide additional recommendations or standards, but the definitive guidelines regarding maximum contaminant levels in the United States are found in the National Primary Drinking Water Regulations.