~ by Nathan Clark, Residential Water Specialist and CWS-1
Iron is the most common metal found in the universe, and makes up at least 5% of the earth’s crust. It stands to reason that some of it would be found in the waters of the earth, including your well water. This is particularly true if you live in the Northeast region, where iron is liberally deposited in the granite strata.
Iron in New Hampshire well water typically comes in four different forms:
- Ferrous iron
- Ferric iron
- Organic iron
- Colloidal iron
Often more than one is present in a single sample. They can all cause staining, a metallic or foul taste, and fouling of pipes and plumbing. This presents a challenge for water conditioning, as different removal methods are required to reduce the iron to acceptable levels.
The two most common types of iron found in well water are ferrous iron and ferric iron.
1. Ferrous iron
Ferrous iron is often called “clear” iron as it is not initially visible in your water. It’s very common in New Hampshire and tends to stain fixtures a reddish-brown color as it is exposed to oxygen, or oxidizing chemicals like soaps or detergents.
Although water softeners can typically remove some iron from your water, the Kinetico Powerline Pro filter series is very reliable in removing challenging ferrous iron. The Kinetico iron filters in the Powerline Pro series draw air into a chamber where the iron is oxidized into particulates. Once the iron is in a particulate state, the system can filter out the iron from the water very effectively.
2. Ferric iron
Iron that is already oxidized (rust), or not in a dissolved state is called ferric iron. A glass of water containing ferric iron will very quickly develop a film of orange on the bottom as the particles settle out of solution. It causes staining of fixtures, laundry, and the dishwasher, as well as fouling plumbing. This form is also very common in New Hampshire’s groundwater.
Because ferric iron is already in a particulate state and not dissolved, it is more readily filtered out of water using a filtration system. Depending on the iron level, a variety of softener solutions will work to remove iron. If the iron levels are high, or if there are other contaminants in the water, other solutions may be required.
Two less common types of iron are organic iron and colloidal iron. Each has peculiar characteristics making them challenging to filter.
3. Organic iron
Ferrous iron that has been metabolized by iron bacteria as part of their diet is called organic iron. These organisms form jelly-like deposits of ferric iron, and can be identified by clumps of iron scum in water and an oily sheen on the surface of water, especially in toilet tanks.
Organic iron is difficult to treat under most circumstances, as the biological scum mass that encapsulates it tends to shield the iron from traditional removal methods. Wells containing iron bacteria should be disinfected with chlorine to kill the problem at the source. The incoming water can also be treated by a chemical feed system that uses a strong oxidizer to destroy the biomass. The residue can then be mechanically filtered out.
4. Colloidal iron
A glass containing water with colloidal iron will have a reddish-pink tinge to it. It is composed of extremely fine particles (smaller than 1 micron), which remain in suspension due to their size and electrical charge. These iron particles are so tiny they have a low specific gravity—practically the same as water. It can take a very long time for them to finally separate from the water.
Colloidal iron also presents a serious challenge for residential filtration, as the most effective removal involves injecting an adhesive agent, such as alum, to bind the tiny particles together into large enough clumps to fall out of solution and be mechanically trapped. Fortunately, this problem is quite rare.
We Can Help Get the Iron Out of Your Drinking Water
If you see the tell-tale signs of any of these four types of iron in your New Hampshire drinking water, contact a certified water specialist for proper testing and treatment.
Learn about other common water problems in New Hampshire.
