Manganese in Water
Manganese (Mn) is often found in surface water and groundwater sources. Usually in combination with iron. The EPA has set Secondary Maximum Contaminant Levels (SMCL) for manganese at 0.05 mg/L, but the EPA does not enforce these guidelines. High levels of manganese can cause black staining in and around water fixtures and often signals high levels of iron mineral deposits in water.
Manganese buildup can reduce a home’s water pressure, and increase plumbing maintenance costs. Levels of manganese above the SMCL can cause staining of laundry and water fixtures and a give a sharp, bitter taste to water.