EPA has established National Secondary Drinking Water Regulations that set non-mandatory “secondary maximum contaminant levels” for 15 contaminants; manganese is one of these contaminants. Water systems use these secondary maximum contaminant levels (SMCLs) as guidelines to manage their drinking water for aesthetic considerations, such as for taste, color and odor. Manganese has a SMCL of 0.05 milligram/liter to control for color and metallic taste.
In 2004, EPA issued a drinking water health advisory for manganese. Health advisories are non-regulatory levels of contaminants to assist public health professionals. Negative health impacts are not anticipated at these concentrations.
EPA provided both short-term and lifetime advisory levels for manganese. One-day and ten-day exposure advisory values for most individuals is the same -- one milligram/liter. EPA suggests that 0.3 milligram/liter be used both as a lifetime advisory value and as a guide for short-term exposures for infants younger than six months of age.
Regulators, utility managers and public health officials use health advisories as they consider what management practices are necessary and when to take additional actions when manganese is found at elevated levels.