Detecting Iron or Manganese in Your Water

If you live in New Hampshire and your home’s water comes from a private well, there may be iron or manganese in your drinking water. Both of these minerals occur naturally in the soil, often dissolving into groundwater as acidic rainfall trickles through the soil and rock. Iron or manganese cause staining on your laundry and water fixtures, gives your water a metallic or sulfur taste, clogs strainers, valves or other plumbing parts, or can leave an oily or “crusty” sheen to the surface of your water.

Before deciding on the type of treatment for removing iron and manganese, you first have to run a water test and identify what type of iron or manganese is present.

•    If the water is clear when it comes from the tap, the iron and manganese are likely in the dissolved form. Called “clear water” iron or manganese, “ferrous” or “manganous,” this is the form of 90 percent of iron and manganese cases in New Hampshire.
•    If water is rusty when poured from the tap it likely contains ferric or manganic particles, which can be brown or black. This affects about 10 percent of New Hampshire cases.
•    The rarest case is when the water has a yellowish tint, but is totally transparent. Called “colloidal iron and manganese,” it is very difficult to remove. The iron and manganese particles are too small to filter and are combined with organic matter in the water, preventing them from settling out. 

Water quality tests must also be conducted to determine treatment, including tests for pH, hardness, dissolved oxygen, and iron and manganese concentrations. Contact the New Hampshire Department of Environmental Services for help or a water treatment specialist to conduct the testing. Once the kind of iron or manganese is identified, you can begin considering treatment options.

•    Oxidation filtration, which injects oxygen into the water, may be one option. While it is effective at removing iron, it requires additional chemical treatment, including chlorine bleach, to remove manganese.
•    A water softener is another option, removing the minerals by running the water through special salt pellets. Softening is simple and inexpensive, but also adds sodium to you water and produces a brine water waste. 
•    Point-of-use reverse osmosis uses a membrane to remove unwanted molecules from the water while letting purified water pass to the other side. While this method is easy to install and is common, it wastes a lot of water.

If you suspect there might be iron or manganese in your water, you see scaling on shower heads or discoloration in sinks and tubs, get your water tested and consider a water filtration system. The state DES can offer advice, or you can call your local water and well technicians, Skillings & Sons.