Coliform Bacteria in Well Water Treatment Guide (Cost & How to Treat) (2023)

Everyone wants to ensure their drinking water is safe, but coliform bacteria can contaminate wells.

What do you do if you have coliform bacteria in well water? Read on for our treatment guide.

What is Coliform Bacteria?

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Coliform bacteria are a group of rod-shaped bacteria found almost everywhere. Coliform bacteria live in soils, organic matter, and even on your skin.

Most coliform bacteria are harmless and won’t cause illness.

There are several different types of coliform bacteria. When testing well water for bacteria, the lab will test for total coliform bacteria.

Total coliform bacteria are in the soil, vegetative matter, and many other places.

Testing for total coliform bacteria is cheap and gives the lab an indication that there may be other bacteria in the water.

Fecal coliform bacteria are a type of total coliform. Fecal coliform bacteria live in the intestines of people and animals. Certain types of fecal coliform bacteria can cause illness.

One bacteria that most people have heard of is E. coli bacteria. E. coli bacteria are a type of fecal coliform that can cause serious illness.

The presence of E. coli in well water is a serious issue that must be addressed immediately.

Testing for total coliforms provides an indicator that other bacteria may be present. If you find total coliforms in your water, the lab will run a test for E. coli as well.

How Do They Get Into Wells?

When constructing a well, the contractor will disinfect and seal off the well to prevent contamination. Over time bacteria can make their way into the well in various ways.

(Video) Solving Bacteria Problems in Wells and Springs

Below are some common issues that allow bacteria to enter wells.

  • Unscreened vents or entry points: When constructing a well, all entry points and vents have a screen placed over them to prevent bugs and small animals from getting into the well. Over time these screens can deteriorate and allow small creatures to enter the well bringing bacteria with them.
  • Groundwater contamination: Your well relies on groundwater to replenish itself. Leaking septic tanks or sewage spills can contaminate the groundwater causing bacterial issues in your well.
  • Surface water entering the well: Occasionally, flooding happens. If the seal on the well has failed, flood water can seep into the well causing contamination. Flood water carries with it a significant amount of bacteria.

Regular inspection of wells will help to prevent coliform contamination. Owners of private wells should inspect their wells at least annually.

The inspection should consist of checking all vents for appropriate screening. You should also inspect the well casing that comes out of the ground.

The casing should extend at least eighteen inches above ground level to prevent water from entering the well. The wellhead must also be sealed properly to prevent contamination.

Signs of Coliform Bacteria Contamination in Water

Unfortunately, it is impossible to tell if coliform bacteria is in your water without a lab test. Coliform bacteria are microscopic organisms that can’t be seen with the naked eye.

There are, however, some signs that will indicate you should get your water tested.

Cloudy Water

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Turbidity and sediment in the well can cause cloudy water. When there is turbidity and sediment in your well, there is a higher likelihood that coliform bacteria are present.

If you notice your water is cloudy, you should test for coliform bacteria.

Discoloration of Water

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Some bacteria cause water to become discolored. If you notice a discoloration in your water, often orange or rusted, there is a possibility that bacteria are present.

Discolored water is a sign you should have your water tested for coliform bacteria.

Strange Odors

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(Video) How to Test Well Water for Bacteria

Bacteria can create strange odors in your water. These odors can be a sulfur smell or some other off odor. If you notice your water doesn’t smell right, have it tested for coliform bacteria.


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Of course, the most serious sign that your water may have coliform bacteria is if you become ill. Bacteria in water can cause intestinal issues such as vomiting and diarrhea.

If you notice your family becoming ill for no apparent reason, definitely have your water tested.

How Much Coliform is Acceptable in Well Water?

According to the Environmental Protection Agency (EPA), no amount of coliform bacteria should be present in drinking water.

The EPA sets maximum limits for contaminants for safe drinking water. The limit they have set for total coliform is zero.

People with private wells should test their water for contaminants regularly. Most local environment departments or health departments offer free water testing for private wells.

You can also contact your local county extension agent.

Just because you find coliforms in your well water does not mean that it will make you sick. Several types of coliform bacteria do not cause illness.

However, the presence of any coliform bacteria indicates there is a potential contamination issue that must be addressed.

How to Treat Coliform in Water

Coliform bacteria are typically removed through chemical disinfection. The addition of chlorine to drinking water will effectively kill coliform bacteria.

When constructing a new well, the driller will add chlorine to the well to disinfect it and kill all bacteria.

If you have contamination in your well, you can disinfect the well with chlorine. Adding chlorine to a well for disinfection is called shocking the well.

(Video) How to Disinfect Your Well Water to Kill Bacteria

Alternatively, if a well is contaminated and disinfection does not work, the water can be filtered to remove coliform bacteria.

How Much Does it Cost to Treat Coliform in Well Water?

The typical cost for shocking a well varies depending on where you live. Costs can be anywhere from $80 to $200.

You can reduce the cost by shocking the well yourself. Most county extension agents in rural areas provide instructions on how to shock a well.

Filtration systems can be a little pricey depending on the product chosen. Typical filtration systems for single-family homes run around $2,000.

If you are dealing with a contaminated well, you should consider filtration and disinfection.

Frequently Asked Questions

Here are the most common questions about bacteria and how you can prevent it from getting into your well water.

Are Coliform and E. Coli the Same?

Coliforms are a group of bacteria. E. coli is a type of coliform bacteria. Typically when you take a water sample to the laboratory, they will test for total coliforms.

Total coliforms are present in the natural environment in soils and vegetation.

E. coli is a type of fecal coliform. Fecal coliforms are in the intestinal tracts of humans and animals and are typically the bacteria that cause illness.

Can a Water Filter Remove Coliform?

Yes, some water filters can remove coliform bacteria. When selecting a filter, you need to be sure to read the label carefully.

Just because a filter removes one thing does not mean it will remove everything.

Most filters are specific for their purpose. For example, filters that remove chlorine or heavy metals may not remove bacteria. Also, filters that remove bacteria may not remove viruses.

When selecting a filter, you also need to consider the volume of water that it can treat.

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Small pitcher filters may be able to remove bacteria, but they are not effective if you need a large quantity of water.

Whole-home filtration systems can treat the main water supply and provide sufficient water for a single-family dwelling.

Which Filter is More Efficient for the Removal of Coliform Bacteria?

A combination filter that includes filtration and disinfection is most efficient for the removal of coliform bacteria. For well systems, a whole-home system works well.

For the physical removal of bacteria, a filter needs a pore size no larger than 0.2 micrometers. E. coli bacteria are typically 2 micrometers long by 0.5 micrometers wide.

For comparison, the average human hair is 70 micrometers wide.

Even with these filters, there is a potential for bacteria to get through. There is also potential for bacterial growth on the filter if they are not maintained and replaced as recommended.

For additional protection, filters need to be paired with disinfection.

Disinfection options include the addition of chemicals like chlorine or utilizing ultraviolet lights to kill bacteria.

Combining filtration with disinfection provides the most efficient removal of coliform bacteria.

Can You Shower in Water With Coliform Bacteria?

Yes, you can shower in water that has coliform bacteria. Taking a shower in water with total coliform bacteria presents a low danger to people.

As long as you don’t drink the water while you are showering, there is little danger.

The presence of total coliform bacteria itself does not present a health hazard for most people.

However, if E. coli bacteria or fecal coliforms are present, people should avoid showering in contaminated water.

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If using the water for brushing your teeth, or washing fruits and vegetables, the water needs to be treated before use. Treat contaminated water by boiling it for at least one minute.


1. How to Disinfect Your Well
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2. BAYWORK & BACWWE Water Treatment Grade T2 and T3 Study Course
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4. Has Your Well Tested Positive for Bacteria? Long-Term Solution to Shock or Sterilize Well Water
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5. How to Disinfect Your Well
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