Iron Levels in Drinking Water

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Iron is one of the most abundant elements on earth. It is an essential element for humans, and it is used in a variety of industrial processes. It is also found in drinking water. High levels of iron can be fatal, but the amount found in drinking water is typically too low to be dangerous. Instead, high levels of iron in drinking water can cause non-health effects, including bad taste and discoloration. If you suspect your water has too much iron, you can test it and treat it.


Iron makes up about 5 percent of the earth's crust. In industry, it is used as a construction material and to create pigments. In humans, it is an essential element required for hemoglobin to transport oxygen from our lungs to our cells.


Iron in Drinking Water

Rainfall seeping through soil causes iron to dissolve and leach into groundwater, including wells and aquifers used to supply drinking water. Iron concentration in wells and aquifers is typically between 0.5 and 10 milligrams per liter, and, as a result of water treatment, iron concentration in drinking water is typically less than 0.3 milligrams per liter. Iron concentrations of higher than 0.3 milligrams per liter in drinking water are noticeable to humans.

Health Effects

For humans, the average lethal dose of iron is quite high -- between 200 and 250 milligrams per kilogram of body weight, or about 14 grams of iron for a typical 70kg adult. Death results from extensive gastrointestinal hemorrhage. However, iron toxicity is rare, and iron intake from drinking water is typically much too low to raise health concerns -- about 0.6 milligrams per day if you're consuming a typical 2 liters of water per day, compared to an average iron intake of 10 to 14 milligrams per day from food.


Other Effects

Although iron in drinking water is not a health concern, it can cause problems. For example, concentrations above 0.3 milligrams per liter can cause food and water to become discolored and taste metallic. Water with a high iron concentration will also stain whatever it is used to wash, including laundry, silverware and bathroom fixtures. Because these effects occur most typically above iron content of 0.3 milligrams per liter, this concentration is typically the upper limit for iron in drinking water.

Testing and Treatment

If you suspect your drinking water may be too high in iron, you can contact your state water department to determine if, and how, your water should be tested. Common sources of iron contamination include pipes or other parts of the plumbing system. Treatment of high iron levels typically involves filtration or some form of chemical removal.