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Iron in drinking water

Also called Fe, Rust, Ferrous iron, Ferric iron.

Legal limit
None
Health goal
None
Federal benchmark
EPA secondary standard for taste, color and staining, not enforceable: 0.3 ppm

Values in parts per million (ppm). Comes from the source.

Contaminant referenceLimits checked Oct. 4, 2026

Where the rules stand

No federal MCL or health goal. EPA's secondary standard is 0.3 ppm (0.3 mg/L), set for rusty color, sediment, metallic taste and reddish or orange staining. EPA does not enforce secondary standards.

The scale every TapBuff report uses for this contaminant: the legal line at the middle, twice it at the right.

Where to find your level

EPA’s national data doesn’t carry iron results for utilities. Your utility’s annual water quality report may list it; on a private well, a lab test will.

What EPA says about health

EPA says contaminants with secondary standards are not considered a health risk at those levels. Penn State Extension says iron is not a health concern in drinking water. Above 0.3 ppm, iron can give water a metallic taste and leave orange or brown stains on sinks and laundry.

Where it comes from

Iron occurs naturally in groundwater. Penn State Extension says it is more common in deeper wells, where water has been in contact with rock longer. EPA notes that corroding iron pipes can also stain fixtures and give water a metallic taste and red color.

What handles it

  • NSF/ANSI 42

    Claim to look for: Iron

    WQA listing wording, under NSF/ANSI 42. On Oct. 4, 2026, WQA showed it only on whole-house systems from one maker. NSF lists iron as a possible 42 claim, but its listing search showed no products with it.

Sources

  1. Secondary Drinking Water Standards: Guidance for Nuisance Chemicals, U.S. EPA. Checked Oct. 4, 2026.
  2. Iron and Manganese in Private Water Systems (updated May 29, 2025), Penn State Extension. Checked Oct. 4, 2026.
  3. NSF/ANSI 42, 53 and 401: Filtration Systems Standards, NSF. Checked Oct. 4, 2026.
  4. Search for NSF Certified Drinking Water Treatment Units (standards and reduction claims lists), NSF. Checked Oct. 4, 2026.
  5. Find WQA Certified Products (Gold Seal listings by standard and claim), Water Quality Association. Checked Oct. 4, 2026.