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Is Water Treatment Needed for Iron in Your Drinking Water?

Posted: April 28, 2016 to

Pure water has no taste, but water is a natural solvent. Most minerals from groundwater, including iron, will be absorbed by water. Most of us don’t like even the idea of iron or an metal in our drinking water. It would be natural to jump the conclusion that you need water quality testing and a water treatment system installed in your home, but wait! Let’s look at it more closely before we make that assumption.

Large amounts of iron in drinking water can give it an unpleasant metallic taste. Iron is an essential element in human nutrition, and the health effects of iron in drinking water may include warding off fatigue and anemia.

Iron in Drinking Water

The thing that you’ll notice the most from water that is high in iron is that the water may taste metallic. The water may be discolored and appear brownish, and it may even contain sediment. Iron will leave red or orange rust stains in the sink, toilet and bathtub or shower. It can build up in your dishwasher and discolor ceramic dishes. It can also enter into the water heater and can get into the laundry equipment and cause stains on clothing. The EPA cautions that although iron in drinking water is safe to ingest, the iron sediments may contain trace impurities or harbor bacteria that can be harmful. Iron bacteria are naturally occurring organisms that can dissolve iron and some other minerals. These bacteria also form a brown slime that can build up in water pipes. Iron bacteria are most commonly problematic in wells, where water has not been chlorinated.

Iron allows red blood cells to deliver oxygen to all cells and tissues in your body. Iron is also a naturally occurring element in nature, meaning you’ll have some in your drinking water. The amount of iron in regular tap water is so minute, however, you probably won’t get sick. But in the rare case that your water does have too much iron, you could experience abdominal and bowel problems. You should be able to tell if your water is overloaded with iron, though — it’ll change colors.

Iron Levels in Water

Generally, the water that comes out of your tap doesn’t have more than 0.3 milligram of iron per liter, the Penn State College of Agricultural Sciences reports. However, if you have well water or if your water comes from a private source, it may not be subject to local or federal mandates. This means your water could have even more iron in these cases. At the very most, your drinking water could have up to 10 milligrams of iron per liter. This is pretty unlikely, though, since your water probably won’t be clear and will likely have a metallic taste.

Types of Iron in Water

If you pour yourself a glass of tap water and it turns brown or red after it sits for a few minutes, you likely have ferrous iron in your water. However, if your water comes out of the tap with a red or yellow tone, your water probably contains ferric iron. While your body can process both types of iron, ferrous iron is easier for your body to absorb. Because it absorbs efficiently at rates as high as 33 percent, according to the Office of Dietary Supplements, ferrous iron might be more likely to make you sick if you have it in your drinking water.

Iron makes up about five percent of the earth’s crust. It can be a soluble or relatively insoluble form found in water. Soluble iron is found in:

  • Groundwater,
  • oxygen-free reservoirs,
  • dead-ends in water distribution systems, and
  • scale (hard mineral coatings) within pipes

When soluble iron is exposed to oxygen or to a disinfectant during water treatment, it oxidizes to the relatively insoluble iron. This is responsible for discolored water.

The primary sources of iron in drinking water are from natural geologic sources and corroding distribution systems and household pipes. Iron-based materials, such as cast iron and galvanized steel, have been widely used in our water distribution systems and household plumbing.

Effects of Iron on Human Health, Water Quality, and Distribution System Infrastructure

Unlike lead and copper, ingesting iron from drinking water is not directly associated with adverse health effects. Although, trace impurities and microorganisms that are absorbed by iron solids may pose health concerns. The effects associated with iron contamination can be grouped into two categories:

  • Aesthetic effects are undesirable tastes or odors. Iron in quantities greater than 0.3 milligrams per liter (mg/L) in drinking water can cause an unpleasant metallic taste and rusty color. Taste is a gauge whether different kinds of treatments effectively removed iron from drinking water. Elevated iron levels can cause drinking water to be a rusty color. This can stain laundry or household items. Discolored water is one of the most frequent consumer complaints about drinking water.
  • Physical effects are damages to water equipment and reduced effectiveness of water treatment for other contaminants. This may cause additional costs water utilities. Corrosion of distribution system pipes can produce sediment or loose deposits that block or slow down water flow.

Corrosion and Metal Solubility Control

Control of corrosion and metal solubility is perhaps the single most cost-effective method for preventing iron contamination. Significant benefits include:

Reducing contaminants in drinking water
Saving costs by extending the useful life of water mains and service lines
Saving energy from transporting water more easily through smoother, non-corroded pipes
Reducing water losses resulting from leaking or broken mains or other plumbing
Managing the acidity, alkalinity, and other water qualities that affect pipes and equipment used to transport water.

Conventional treatments can be used to remove secondary contaminants, such as iron, from our drinking water. These treatments include:

  • coagulation/flocculation,
  • filtration,
  • aeration, and
  • the use of granular activated carbon.

Nonconventional treatments include:

  • distillation,
  • reverse osmosis, and
  • electrodialysis.

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