Manganese is a metal found in rocks and soil. It enters water through erosion and industrial processes. While essential in small amounts, excess can harm the nervous system.

Manganese has been used for centuries, from ancient glassmaking to modern steel production. While naturally occurring, human activities like mining and manufacturing can increase its presence in water. The EPA doesn't regulate manganese as a primary contaminant but suggests a secondary standard for taste and staining. Water treatment plants can remove excess manganese through oxidation and filtration. Home water softeners may also help reduce levels in well water.