What is the Secondary MCL for copper?

The Secondary Maximum Contaminant Level (MCL) for copper is established primarily to address aesthetic concerns, such as taste and odor, rather than health risks. The correct value of 1.0 mg/l reflects the level set by the EPA for copper. This guideline helps to ensure that the water received by consumers is not only safe but also meets their quality preferences in terms of taste.

Copper can naturally occur in water and also may come from plumbing systems, thus monitoring its concentration is crucial. A level above the Secondary MCL could lead to noticeable metallic tastes in water, prompting public complaints. Keeping the concentration at or below this threshold helps maintain water quality while ensuring that it remains palatable for consumers.