Iron bacteria in well water and how to remove them?

Are you one of the nearly 45 million Americans who get their water from a private well? Are there iron bacteria in the well water? This could be the case if your water is rusty or stinks. Don’t worry, it’s a very common well water problem.

While iron bacteria do not pose a health risk, they can damage your home and even other water treatment equipment. Worse, iron bacteria are often misdiagnosed. If treated incorrectly, small problems can become significantly worse.

What are Iron bacteria?

Iron bacteria are small living organisms that occur naturally in soil, shallow groundwater, and surface water. These bacteria combine iron (or manganese) and oxygen to form deposits of “rust”, bacterial cells, and a slimy material that adheres the bacteria to well pipes, pumps, and plumbing fixtures.

Iron bacteria are microorganisms that occur in the soil, in iron-rich groundwater, and in surface water. Similar to iron deposits in the soil, iron bacteria enter the aquifer (well water source) through rain or underground seismic movements.

Although normally harmless, iron bacteria eat and break down the iron molecules when they have access to oxygen (especially when it is in high concentration).

This leads to bacterial overgrowth. Since well water is rich in iron and other minerals, the iron bacteria in well water reservoirs have favorable conditions for reproduction.

Once the bacteria have dissolved enough iron, they excrete rust-colored slime in the water.

When this happens, the rust-colored, slimy organisms migrate through the water or well system and attach to surfaces.

These finishes include everything from the well reservoir to the pipes that distribute water throughout the home. You may experience a slimy sensation or a metallic taste in your water at some point.

What are the effects of iron bacteria?

The dramatic effects of iron bacteria can be seen in surface water – brown, slimy masses at the bottom of streams and sea shore and an oily sheen on the water. Iron bacterial infestation in wells can cause:

  • Unpleasant taste and/or odor reminiscent of heating oil, sewage, or decaying vegetation.
  • Reduced well yields due to biofilm clogging.
  • Rusty slime deposits in the toilet tank, on filters, or inside the fountain body.
  • Premature corrosion of downhole components.
  • Difficulty eliminating coliform bacteria as the biofilm protects the bacteria from the chlorine disinfectant.
  • Expensive and difficult well rehabilitation

How to Detect Iron Bacteria

Tastes and Odors

  • Swampy, oily or petroleum, cucumber, sewage, rotten vegetation, or musty.
  • May be more noticeable after the water has not been used for a while.


  • Yellow, orange, red, or brown stains and colored water.
  • Rainbow-colored, oil-like sheen.

Red Slimy Deposits

  • Sticky rusty, yellow, brown, or grey slime.
  • “Feathery” or filamentous growths (especially in standing water).

You can confirm that it is iron bacteria by having the water tested at a laboratory.

How to Remove Iron Bacteria From Well Water

There are a number of methods and treatments specifically designed to remove iron bacteria from private well water sources. Physical removal, shock chlorination, and continuous disinfection can be used for this.

Physical Removal

The first step in treating iron bacteria is physical removal. A professional plumber or handyman is best suited for this job.

First, your well equipment is removed and cleaned. A plumber will also clean the inside of your fountain casing and prepare the system for chemical treatment.

Shock Chlorination

If you’re struggling with a particularly bad iron bacteria problem, shock chlorination may be the best option for you.

This method removes most bacteria immediately. If iron bacteria have accumulated over a period of months or years, shock chlorination is effective enough to solve the problem.

In chlorine shock disinfection, household bleach or a similar disinfectant is circulated through well water systems and household plumbing. One to two weeks after performing this treatment, you should retest your well water to determine bacterial levels.

Note that chlorine, while cheap, is not always the most effective remedy. You may need to use chlorine more than once to treat your well. Make sure you’re using the right concentration of chlorine to effectively address the problem.

You can use around 200ppm of chlorine to combat iron and sulfur bacteria. If you are not using a continuous disinfection system, you may need to shock your system 2-3 times a year.

Continuous Disinfection

Shock chlorination can remove most of the iron bacteria from the water. However, this type of water treatment may not be able to reach all bacteria, as layered deposits often occur.

Prolonged and long-term contact with a disinfectant is required to kill bacteria and keep them at bay.

This method follows these steps:

1) Chemical Injection

Chemical injection is one of the most common and effective means of long-term removal of iron bacteria.

This water treatment process uses the same method as a municipal water utility. The system injects a chemical – usually chlorine – into your water that acts as a disinfectant, killing ferrous bacteria and similar organisms.

2) Retention

After injection, your drinking water must sit in a storage tank for a few minutes before it can be used.

Chlorine cannot kill bacteria immediately. Instead of going straight into your home, the water is held in a holding tank long enough for the chlorine to do its job. The size of this tank determines how much water is available to you at any given time.

3) Filtration

The final step in continuous disinfection is to remove contaminants from the water, including bacteria and oxidized metals, as well as disinfectant chemicals.

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