Iron is a naturally occurring mineral widely present in the Earth’s crust, making its presence in private well water supplies common. As groundwater moves through soil and rock, it dissolves small amounts of iron and carries them into the aquifer. While iron is an essential nutrient for human health, excessive concentrations can raise concerns for homeowners.
Understanding the Health Implications of Iron Consumption
For the vast majority of healthy individuals, the iron found in typical well water concentrations is not considered a primary health concern. The human body is designed to absorb iron primarily from food sources, and it generally does not absorb the mineral from water easily. The Environmental Protection Agency (EPA) does not regulate iron as a primary contaminant that poses a direct health risk.
The body’s natural regulatory systems usually prevent iron overload, but this mechanism fails in people with a genetic predisposition. The most significant health risk associated with iron ingestion is for those who have hereditary hemochromatosis, a genetic disorder. Individuals with this condition absorb an abnormally high amount of iron from their diet and water, leading to accumulation in major organs.
Chronic iron overload in these genetically susceptible individuals can cause serious damage to the liver, heart, and pancreas over time. Acute iron poisoning is extremely rare from water alone and is typically the result of supplement overdose. In some cases of very high intake, consuming iron-rich water may cause temporary gastrointestinal upset, such as nausea or diarrhea.
Practical Problems Caused by Iron in Well Water
While health risks are generally low, high iron concentrations cause aesthetic and functional problems that prompt homeowners to seek treatment. The presence of iron gives water an objectionable, metallic taste and can also create a rust or earthy odor. High levels of the mineral often cause water to appear discolored, ranging from yellow to red or brownish-red.
These high concentrations lead to visible reddish-brown or orange staining on plumbing fixtures, dishes, and laundry, which is difficult to remove. The EPA established a Secondary Maximum Contaminant Level (SMCL) for iron at 0.3 milligrams per liter (mg/L). This standard is not based on health threats but rather on the desire to avoid these aesthetic nuisances.
Beyond cosmetic issues, iron can reduce the overall efficiency and lifespan of a home’s water system. Iron particles may build up as a hard scale inside pipes, causing significant clogs and restricting water flow over time. This mineral buildup can also reduce the operating efficiency of water-using appliances, such as dishwashers and water heaters, increasing maintenance costs.
Testing and Effective Iron Removal Methods
The first step in addressing an iron problem is professional water testing to determine the exact concentration and, more importantly, the form of iron present. Iron typically exists in two main forms in well water: ferrous and ferric, and the treatment method must be tailored to the specific form. Ferrous iron is dissolved in the water and is often called “clear-water iron” because the water appears clear when it first comes out of the tap.
When ferrous iron is exposed to air, it oxidizes and converts into ferric iron, which is insoluble and precipitates out as visible reddish-brown particles, known as “red-water iron.” For low concentrations of dissolved ferrous iron, typically below 3 to 5 mg/L, a traditional ion exchange water softener may be effective. However, using a water softener for higher loads of iron can damage the resin over time, making oxidation and filtration a more robust solution.
Oxidation and Filtration
Oxidation involves converting the dissolved ferrous iron into the solid ferric form, allowing it to be filtered out. This can be achieved through methods like aeration, which mixes the water with air, or by injecting an oxidizing chemical such as chlorine or potassium permanganate. Once oxidized, the iron is removed using a filter media, like manganese greensand or catalytic filtration, which traps the solid particles.
If iron bacteria are also present, which feed on iron and create a problematic slime or biofilm, the well may first require shock chlorination to eliminate the organisms. For water containing only the precipitated ferric iron, a simple sediment filter or a backwashing iron filter is often sufficient to physically remove the visible particles. A qualified water treatment professional can recommend the best system based on a complete analysis of the water chemistry.