Manganese Contamination in California

ZipCheckup analyzed drinking water data across 2,630 ZIP codes in California for manganese contamination. 194 ZIP codes have reported manganese detections, and 81 have EPA violations on record.

The violation rate for manganese in California is 3.1% of all ZIP codes — roughly in line with the national average.

EPA Standard for Manganese

The EPA maximum contaminant level (MCL) for manganese is 50 µg/L (SMCL / health advisory), governed by the Secondary Drinking Water Standards. Water systems that exceed this limit must take corrective action and notify consumers.

Worst ZIP Codes for Manganese in California

These ZIP codes reported the highest manganese levels in California based on CCR reports and EPA data:

Lowest Manganese Levels in California

These ZIP codes had the lowest reported manganese detections in California:

Health Effects of Manganese

At elevated levels, manganese causes neurological effects similar to Parkinson's disease (tremors, difficulty walking). Infants and children are most vulnerable — studies link high manganese in water to lower IQ and behavioral problems.

How to Remove Manganese From Drinking Water

The most effective treatment for manganese removal is Oxidation Filter or Reverse Osmosis. Look for filters certified under NSF 42 / NSF 58 standards.

Check Your ZIP Code

Use the ZipCheckup water quality search to see manganese data for your specific water system in California.