What to Do About Coliform in Well Water

What to Do About Coliform in Well Water featured photo

Water is essential but what happens if they end up contaminated with not only sediments but also bacteria? With growing concerns over health risks, many wonder what to do about coliform in well water.

If your water tested positive for total coliform, have a new sample tested to confirm the results. Do not use your water and find an alternative source in the meantime. Fix the contamination with any of these methods: shock chlorination, continuous chlorination, or UV purification. Then, have your water tested again and hope for negative results.

If you have trouble dealing with the contamination that occurred in your home’s private well, you can always ask a professional for n inspection. From there, you can consult for the best course of action you should take.

Below, we’ll go over everything you need to know about coliform bacteria and how they could get into well water. Then we’ll cover what you should do in the case of coliform contamination.

What is Coliform?

Everyone needs clean, safe water. We use water for everyday activities including drinking, cooking, bathing, cleaning, and so much more.

Contaminants and bacteria are all around us and several water sources, including well water, are susceptible to be contaminated.

One common contaminant that has many homeowners worried is coliform.

Coliform bacteria, or total coliform, are a large group of different naturally occurring types of bacteria. They are commonly found in the environment and everywhere around us.

Coliform can be present in the soil, surface water, decaying vegetation, plants, and in the digestive tracts of warm-blooded animals and humans and in their wastes.

What does a positive result mean?

Coliform bacteria are generally safe and are not particularly dangerous or harmful to humans. Their presence in your well water after a certified water test isn’t a cause for panic.

Coliform is also known as “indicator” organisms. This means a positive water test result could indicate the possibility of other disease-causing bacteria present in the water.

Their presence could mean that a pathway of contamination between the water source and the water supply exists.

Though coliform, generally, shouldn’t be a cause for panic, there are, however, certain strains of it – like E. coli – that pose major health risks to humans and anyone who drinks them.

Fecal coliform

Fecal coliform is a type and subset of coliform bacteria specifically found and present in the gut and feces of warm-blooded animals.

When your water supply has tested positive for fecal coliform, this is a positive indication of the presence of human or animal waste.

Escherichia coli, or E. coli

E. coli, or Escherichia coli, is a type of fecal coliform bacteria. There is also more than one type of E.coli. 

A positive water test result for E. coli indicates the presence of either animal or human feces in your water supply. This is considered the best indicator of possible harmful pathogen presence in your water.

Testing Your Water for Coliform

Well water isn’t regulated by the government or any regulating body. Relying on well water as your primary source of water means the responsibility for its safety for use and consumption lies solely on the homeowner.

To protect your household from harmful contaminants and pathogens, it’s generally recommended to test your water for coliform annually.

Annual testing is essential even if you don’t notice any changes in your water because you simply cannot tell if there is contamination only through the taste, smell, or look of the water.

Though DIY water testing kits are readily available in the market, it would still be best to have a professional do your annual water testing.

Water testing by certified laboratories may range anywhere from $10 to $100.

How Does Coliform Get into Well Water?

There are many ways for coliform bacteria to find a pathway to contaminate your well’s water supply:

  • Heavy rain or flooded area
  • A malfunctioning and leaking septic system
  • Surface water runoff
  • Cracked, broken, or damaged well components and parts
  • Agricultural runoff
  • Well cap is not properly sealed
  • Poor well materials or construction

Coliform bacteria should not contaminate wells under normal circumstances. If your water supply did test positive for them, then further investigation of what the source is should be conducted.

Health Concerns Associated with Coliform

Many forms of coliform bacteria are actually harmless to humans and don’t pose a health risk at all. But some strains, like E. coli, can make people sick and can be dangerous.

Some symptoms one may experience include headaches, nausea, upset stomach, cramps, fever, vomiting, and diarrhea. Some worse symptoms could even lead to kidney failure and other harmful long-term side effects.

A positive coliform water test result should not be taken lightly as it could only indicate the presence of more dangerous pathogens in your water supply.

Households with infants, young children, the elderly, and compromised individuals should take extra precautions. These groups tend to have weaker immune systems to fight off the bacteria.

What to Do About Coliform Bacteria in Well Water

If you got a positive coliform water test result, here’s what you need to do to take action:

  1. Retest water to confirm results

If you received a positive water test result for total coliform bacteria, have a new sample tested specifically for fecal coliform bacteria or E. coli.

For retesting, you’d want to make sure you don’t contaminate the water sample. When collecting new water, follow the lab’s precise instructions.

Make sure to wash your hands and don’t touch the inside of the container as there is a possibility that this is causing a positive result.

Also, use a different faucet than what you used in the first water sample that tested positive.

  1. Stop using the water

Until you receive the results of the retesting, stop using your well water altogether. Find a temporary alternative source of water. In the meantime, buy bottled water. 

If that isn’t possible, boil the water for one full minute to get rid of the bacteria. You can boil and save the water for later use. Use this for drinking, cooking, and brushing your teeth to be safe.

  1. Fix and treat the problem

The next essential step is to find the source of the contamination and fix the problem. Here’s what you can do to solve the issue:

  • Chlorine Shock 

Shock chlorination is a disinfecting method that uses a very concentrated solution of chlorine for at least 12-24 hours before purging the water. This essentially “shocks” the well to disinfect it from bacteria contamination.

The amount of chlorine to use will depend on the depth and diameter of your well and the water level.

Chlorine is hazardous so safety precautions must be kept in mind while doing this. Use protective goggles, gloves, and aprons for safety. Or better yet, call in a professional to do it for you.

Shock chlorination is only a temporary solution and can be your best bet if the cause for contamination is a one-off chance like flooding. But if you need something more permanent, this may not be the best solution for you.

This method can take a few days to complete and during that time, your water is not safe to drink so find alternative sources.

  • Continuous chlorination

Continuous chlorination uses a disinfection treatment system that continuously treats water coming into your home. This method injects a chlorine solution or dry powder into the water before the storage tank.

This is a much more reliable option to solve your problems with coliform as it disinfects water 24/7.

  • UV purification

UV purification disinfects well water without adding any chemicals or additives into the water. This ensures treating the water wouldn’t change how it smells or tastes.

This uses UV radiation through a glass sleeve. As the water and pathogens get exposed to the UV bulb, they get disinfected.

The UV purification method often also filters out sediment in the last stage of the process.

This is a low-maintenance disinfecting method. You only need to change the UV lamp at least once a year. It does, however, use electricity so you may notice a small spike in your electrical bill.

  1. Test the water again

After going through your preferred well disinfection method, have your well water tested again. Wait for the results before consumption.

Once the negative results come in, consider regular annual testing to ensure safe water quality.


One common water source across the country is private wells. Private well owners carry the responsibility of keeping their drinking water clean and safe for consumption. So what happens when your well water tests positive for coliform?

Coliform bacteria is often an indication that harmful pathogens may be lurking in your water supply. Here’s what you should do: first, you need to get another sample and have it retested for confirmation. In the meantime, stop using the water. There are three main methods you can fix the issue: shock chlorination, continuous chlorination, or UV purification. After going through your preferred method, have your water tested again and hope for a negative result.

And that has been our detailed guide on what to do about coliform in well water. Don’t hesitate to reach out to us below with your other queries!

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