Sulfate is a mineral that enters water from soil and rocks. High levels can cause digestive issues. It's used in water treatment and contributes to water hardness.

Sulfate occurs naturally in groundwater as it dissolves from mineral deposits. It's commonly found in sedimentary rocks and soil. Water treatment plants may add sulfate compounds for pH adjustment. While essential for plant growth, high sulfate levels in drinking water can impart a bitter taste and potentially cause temporary laxative effects in some individuals. Sulfate is measured in milligrams per liter (mg/L) and contributes to water hardness. The EPA recommends a secondary maximum contaminant level of 250 mg/L for aesthetic reasons.