What is the Maximum Contaminant Level (MCL) for the secondary standard for sulfate?

The Maximum Contaminant Level (MCL) for the secondary standard for sulfate is set at 250 mg/l. This standard is part of the guidelines established by the Environmental Protection Agency (EPA) to protect public health and the environment. Secondary standards are not enforceable, but they serve as guidelines to help manage contaminants that may affect the aesthetic qualities of drinking water, including taste, odor, or appearance.

Sulfate can naturally occur in water from the dissolution of minerals, and while it is generally not harmful at low concentrations, high levels can lead to a bitter taste and may also cause issues such as laxative effects in some individuals when consumed in larger quantities. By establishing a guideline of 250 mg/l, the MCL aims to minimize potential taste and health issues for consumers while providing a margin for safety. This standard reflects a balance between protecting public welfare and recognizing that sulfate is commonly found in various water sources.