IRON FACT SHEET

Brief Overview:
Contaminant: Iron
Category: Inorganic
MCL: 0.3 mg/L
Source: Occurs naturally in ground water
Effect: Offensive taste, odor, and staining
Followup: Treat and retest
Treatment: Oxidation filters, Particulate filters, Ion exchange

Details:
Source:
Iron can occur naturally in ground water and it is often found in combination with manganese. Iron can also occur in drinking water from corroding pipes. While iron chemistry can be complex, the two basic forms of iron in well water are red water iron and clear water iron. Red water iron appears red when it comes out of the tap. Clear water iron appears clear when first drawn and turns red after exposure to air. Some of each type may be present in a water supply. Clear water iron is sometimes called ferrous iron, while red water iron is called ferric iron. Other complex forms of iron are colloidal, organic, and bacteria.

Effect:
Except in rare instances, iron in drinking water is not considered a health problem. In fact, small amounts of iron (1 to 2 mg) are essential to human health. Concentrations > 0.3 mg/L may cause the water to have an unpleasant metallic taste, and may cause reddish-brown stains on clothing or household fixtures.

Followup:
If the water has been out of use, put the water back into use and retest. If iron persists, install a treatment system and retest.

Treatment:
Iron can be removed by oxidation and conventional treatment and by an ion-exchange method specifically designed for iron removal. Utilization of the “manganese greensand” filter using potassium permanganate to oxidize the iron is also an effective method to remove iron. Mechanical filtration will remove red water iron, while clear water iron will require oxidation/filtration or removal by ion exchange. When the source of iron is the corrosion of pipes and other water-contact surfaces, stabilization or other appropriate water treatment processes can be employed to minimize introduction of iron into the water. Since iron can be difficult to remove from water, an experienced water treatment specialist should be contacted.