What's on tap: Iron, rust and corrosion in drinking water


Iron Iron (Fe) is the fourth most abundant element on Earth. Making up approximately 35% of Earth's mass, scientists suspect it's one of three elements that make up its core. Often considered one of the most important types of metal, approximately 90% of metal that is refined is iron. In addition to its well-known industrial uses, iron is critical to human, plant and animal life. It's a key component of hemoglobin, the substance that carries oxygen within red blood cells. Patients are treated for anemia with iron sulfate. Similarly, iron helps plants create chlorophyll. Rust The textbook definition of rust is "a reddish substance that forms on iron or some other metal usually when it comes in contact with moisture or air." In other words, rust is a close relative of iron because rust couldn't develop without iron. A type of corrosion, rusting slowly breaks down iron resulting in reddish brown flakey material.


Because of its tremendous natural prevalence on earth, iron and rust easily enter our local water supply. As water percolates through soil and rocks, it dissolves minerals containing iron and then carries the elements to water sources. Along the way, water often picks up bits of naturally occurring rust from the earth, then both are collected in streams, ponds, rivers and lakes. These water sources then feed into our drinking water, further transporting the iron and rust, which eventually enters our household plumbing system. Additionally, as iron is a very common metal used for plumbing, rusty water is common as old pipes corrode. Rusty water can also come from well water that has high iron levels.


Elevated iron levels in water are often very easy to detect with the naked eye. It will give water an unpleasant color yellowish, red or brown and take on a distinctive metallic flavor. In some cases, iron-rich water can even smell bad. Discoloration is a result of the iron being exposed to oxygen as it leaves a water source. Sometimes it's not visually obvious that your water contains high levels of iron or rust. There are a few signs that you can watch for that indicate iron in your water:

  • Dry, itchy skin
  • Dull hair
  • Worn, scratchy clothes
  • Lime scale or other build up around drains, faucets and fixtures
  • Water that takes a lot of soap or time to lather
  • Rust-colored staining in sinks, toilets, washing machine, and bathtubs or showers
  • Bits of chunky matter in your water glass


Rust Bits of rust floating in our water systems can amalgamate or clump up, causing slowed or blocked water flow. A small amount of rust is normal, and can easily be addressed by simply flushing your plumbing system. However, a higher quantity can indicate severe deterioration of your plumbing that would require new pipes. Iron When it comes to your health, iron is a complicated element that cannot simply be labeled good or bad. While iron is critical to our well-being, too much of it can be harmful. In addition to discoloration and staining causing damage to your home and household goods, prolonged exposure can be toxic and harm your DNA, proteins, and lipids and cause mysterious skin conditions. In one case of high iron levels, a 63-year-old woman literally sweated rust staining her clothes, bedding and other items she touched. Profiled on an episode of The Doctors, a thorough investigation of the woman's home discovered that water in her well contained 10 times the safe amount of iron. A medical exam revealed the extreme amount of iron caused her to develop pseudochromhidrosis a rare condition related to the sweat glands. Her prognosis is good, and with a powerful water filtration system, her sweat is expected to lose its rust color in time.


If your water has a metallic taste, odd smell and/or is causing discoloration of your sink or tub, you very well may have iron in your water. To find out for sure if you have an iron problem in your plumbing, you will need to test your water. At-home test kits are an easy way to check your water quality. Be sure to select a test that looks for iron, not all water tests will detect it. These tests are also effective options for well water, or when you're not located in a municipality. State-certified labs can also test your water. In addition, you can contact the EPA Office of Ground & Drinking Water for information on water in your area. They have water quality reports that will tell you if the high iron levels are limited to your home, or are part of your community.


Iron and rust are not considered health threatening for two main reasons. First, iron is necessary for a healthy body. Second, because the level of iron needs to be quite high for it to become a risk and it's unlikely to find drinking water that contains iron in those significant amounts. For iron to be deadly, it takes between 200 and 250 milligrams per kilogram of body weight, or about 14 grams of iron for a typical 70 kg adult. That's like consuming 14 paperclips worth of iron. Considering these factors, the EPA recommends that safe water includes 0.3 parts per million (ppm) of iron, not to exceed 10 ppm. Public water systems only need to test for them on a voluntary basis. In addition, the EPA has placed iron on the National Secondary Drinking Water Regulations, stating, "If these contaminants are present in your water at levels above these standards, the contaminants may cause the water to appear cloudy or colored, or to taste or smell bad. This may cause a great number of people to stop using water from their public water system even though the water is actually safe to drink."


Iron is generally easy to remove from water. Simple filtration systems can remove most iron from water, restoring a home's supply to the clear, clean-tasting water we depend on. The results of a water test will give you helpful information for choosing the right filter because the level of iron present in your water will dictate which filter will perform best.


While there are a variety of iron filters on the market, these are a few highly rated top performers:


Regular replacement of the filter and/or cartridge is critical to maintaining their effectiveness and reducing bacterial contamination. An overused or out-of-date filter can become dangerous because the filter will no longer trap contaminants, allowing them to leach back into your water. For the safety of you and your loved ones, it's important not to put off replacement too long. There are four effective ways of knowing when it's time to replace your water filter:

  1. Follow the manufacturer's recommendations. Their specified replacement timing will err on the side of caution so you can be assured that your water quality will always be safe.
  2. Measure usage. Install a filter measurement meter or filter monitor that connects to the incoming water line that feeds the filter system and measures the number of gallons that pass through. Then using the manufacturer's recommended usage limit, program the monitor to alert you when you've reached the allowed number of gallons. You'll know exactly when it's time to replace the filter.
  3. Read your water bill. If your home is supplied with municipal water, your water bill will tell you exactly how much water is used monthly. Compare your actual usage to the manufacturer's recommendation and plan the replacement accordingly.
  4. Monitor manually. If you have non-municipal water, the most cost effective method is to monitor your filter manually either with your palate or a water testing kit. Start with routine water tests that look for lead, microorganisms and other contaminants to verify whether your filters are still removing them. For drinking water systems, simply fill a glass with water and check the flavor yourself. You'll be able to see or taste when the filter is exhausted and no longer purifying your water because the water flavor will be unpleasant.


For answers to alkalinity-related questions, recommendations on the best filter for your home or general drinking water questions, contact us.