Response: Your drinking water may be brown because it has too much iron in it. Iron is a common, naturally occurring metal in soil, and as a result, is normally present in your drinking water. Under normal conditions, drinking water provides about 5% of the iron that you are supposed to drink or eat each day. You need iron to survive, as iron is an key part of red blood cells and is used to trap oxygen and carry it from your lungs to other parts of your body.
Although not dangerous to drink, brown water is unappealing and annoying. Iron-containing water may have a funny, metallic taste and may stain anything white, including your clothes, toilets, bathtubs, and other surfaces.
Iron can get into your water in several ways. One of the most common ways is when rust gets dislodged from water pipes. This can happen when pressure in the pipes changes, for example when water pipes are repaired or when water in the pipes is shut off and then turned back on again. If you get water from a well, it is also possible that more iron than normal entered your well water from the surrounding soil and dirt. You can try an easy and quick fix to clear your water by running the cold water for about 20 minutes. If your water is still brown (and if you get your water from a public system), you should call the town or city to ask whether the brown water is from the city's pipes. If it is from the city pipes, the city should send someone out to flush the brown water out from a nearby fire hydrant.
If these methods are unsuccessful, you will need to try other, more complicated treatment methods, such as aeration, filtration, chlorination, water softeners, and ozonation. The right treatment method for you will depend on several factors, including the exact form of iron in your water, the temperature, acidity (pH), and pressure of your water, and how much you are willing to pay and maintain your system. Since it is fairly complicated to figure all of this out, you should get the help of a certified water laboratory -- the names of which should be listed on your state (or if you live outside the US, country's) environmental agency web sites. The testing laboratory will test your water for iron, temperature, pH, and hardness. Based on the answers, you will be able to choose between one or several treatment options.
You can double check the lab's answers by looking at how the iron in your water behaves. For example, if your water runs clear but turns brown after a few minutes, you have ferrous iron or rust in your water. In this case, you will have many treatment options, including probably the simplest option -- aeration and filtration (if your water fits within a certain temperature range) -- and the most expensive option, ozonation.
On the other hand, if your water is rust colored as soon as you pour it, it contains either ferric iron or organic iron. It is ferric iron if brown particles start to settle on the bottom of your glass. In this case, treatment options will be more straight-forward, including only filtration-based methods. If your glass remains particle free after several minutes, your water contains organic iron; this generally only occurs if your water comes from a well. Treatment options include water softeners, filtration, and ozonation.
For more detailed options on treatment methods, you should check out this document. I think that it is pretty good.
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Helen Suh MacIntosh is a professor in environmental health at Harvard University and studies how pollution behaves in the environment and how it affects people's health. Please keep in mind that her answers are just her interpretation of available information and should not be taken as the only viewpoint or solution to a problem. Use this column at your own risk. Having said this, please feel free to post any of your environmental health questions to email@example.com (please use a descriptive email subject line and mention if you want to remain anonymous or not).