Iron is one of the earth's most plentiful resources, making up at least five percent of the earth's crust. Iron in well water is usually found in a dissolved state and may appear clear when first drawn from the tap.

The maximum amount recommended in water is 0.3 mg/L which is same as saying 0.3 Parts Per Million or PPM. When the level of iron in water exceeds the 0.3 mg/l limit, the water may have a red, brown, or yellow color and stain laundry and fixtures.  Red, brown or yellow well water is often a sign of too much iron.

Iron in water may also cause a metallic taste and an offensive odor. Water system piping and fixtures can become restricted or clogged.  Appliances such as water heaters, dishwashers and washing machines can get plugged up with rust and sediment.

Iron gives water a disagreeable metallic taste. When the iron combines with tea, coffee and other beverages, it produces an inky, black appearance and a rusty, bad taste.

There are four main types of iron in water or conditions in which iron is found in well water:

• Soluble “Clear Water” Iron
• Insoluble Oxidized “Red Water” Iron
• Organic Iron
• Iron Bacteria

Questions to Ask When Choosing an Iron Filter:

1. What type of iron do I have in my water?

2. What is the flow rate that I have available, to backwash the iron filter I choose?

3. Do I have manganese, hydrogen sulfide odor, iron bacteria or tannin in my water?

4. What is the pH (acid or alkaline nature) of my water?

5. According to the water test results, will the water treatment unit remove the total iron concentration?

Test Your Water

If there is a high iron problem with the water supply, the first step is to determine the source. The source of iron may be from the corrosion of iron or steel pipes or other components of the plumbing system where the acidity of the water, measured as pH, is below 6.8.

A water test to determine  iron, pH, manganese, hardness, and total dissolved solids is a good place to begin. If the water direct from the well has a yellow or tea colored look to it, an additional test for tannin is recommended as well. Take the sample as close to the well as possible.

With these results, you can identify if you need any type of water treatment and what type of system to select based on your water chemistry. 

If the source of water is a public water system and you experience iron-related problems, it is important to contact a utility official to determine whether the red water is from the public system or from the home's plumbing or piping.

Click here to learn more about Chlorination Systems for Well & Spring Water.

Estimate Chlorine Demand for Chlorine Water Treatment

When chlorine is added to water, it reacts with bacteria and other impurities, such as hydrogen sulfide, soluble metals, organic matter particles, and other microorganisms. The chlorine demand must first be satisfied before a residual chlorine concentration can establish.

Once there is a residual chlorine concentration, this residual concentration must maintain during the required contact time to kill pathogenic microorganisms. To adequately disinfect the water, it is required to supply the water with a higher chlorine concentration than the concentration required to kill bacteria.

Chlorine demand is how much available, or “free” chlorine in mg/L or PPM is needed to kill the bacteria, remove odor, and/or oxidize iron to achieve your goals.

Amount of chlorine required to kill bacteria and oxidize iron, manganese, and hydrogen sulfide:

* Based on CT Values recommended by USEPA. CT value is the Concentration of chlorine multiplied by Time in retention. C x T = CT value. The less Concentration of chlorine you have, the longer the contact time required.

Example: Common well water analysis and chlorine demand calculation:

Note, calculations for Chlorine Demand do not have to be exact. Once the system is up and running, a simple free-chlorine test will let you know your chlorine demand after the contact tank. The chlorinator can then be easily adjusted to put out more or less chlorine as needed.