Coliform Bacteria is an indicator bacteria, meaning it could be a disease-causing pathogen. Escherichia coli (e.coli) means you have fecal matter in your drinking water. Coliform bacteria contamination in your well water could be caused by an animal or insect in your well, or septic waste entering your water supply.

While some forms of bacteria are naturally found in soil and plants, understanding the type of bacteria in drinking water can only be determined through proper testing.

We can solve your coliform bacteria problem with a UV light system. This could save you money when considering the cost of relocating or the potential damage that could be done to your water softener if you leave it untreated. This can help protect you and your family and the home’s value when considering a sale.



  • Bacteria that could cause diarrhea and vomiting
  • Protozoa that can cause dysentery
  • Viruses that cause polio and hepatitis
  • Helminths, roundworms, and tapeworms that cause chronic diarrhea

These pathogens could potentially harm children and the elderly more substantially if there is water contamination.

My water tested positive for Coliform Bacteria. What do I do next?

Do not drink the water. You can switch to bottled water or boil your water for at least one minute. The first recommended option to treat for bacteria is to chlorinate your well. H2O can provide this service. Then, retest for bacteria. If the second test is positive, you can chlorinate the well again and retest. To permanently treat for bacteria, many customers prefer us to install a UV light system over the well chlorination option. You should also try to determine the source of water contamination. We can check your well for animals that may have fallen in, insect nests, and other potential reasons for the contamination like a well cap that is not sealed properly.

coliform bacteria in well water

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At H2O, our water specialists can pull a sample for bacteria and send it to a lab for a fee if you are in our service area. You can also contact a Certified Laboratory.

How can I protect my well water?

  • Test annually for bacteria
  • Install a bug-proof, code compliant, water-tight well cap and ensure it remains properly secured and maintained
  • Make sure your well casing is at least 15 inches above the ground
  • Consistently maintain all exposed elements of your well and replace or repair at first signs of damage
  • The ground must slope AWAY from your well casing to keep surface water out.
  • Any time your well is serviced – make sure the well is chlorinated
  • Maintain accurate records of any well maintenance
  • Inspect your septic system regularly
  • Avoid using fertilizers, pesticides, gasoline, etc. near your well

How often should I test my water for bacteria?

The State of Connecticut Department of Public Health recommends that you test your water semi-annually (spring/fall) for total coliform bacteria, nitrate, pH, sodium, turbidity, and color. Consider additional testing after land disturbances such as flooding, new construction, or industrial activity. Anything that may cause a ground disturbance near your well could cause water contamination.

Any change in odor, color, or taste in your water can signify a contamination problem.

If you are purchasing a home with a well, while there are no state requirements, it can be valuable to know if the existing well contains contaminants and requires treatment.

Even with a proven treatment system, it is crucial to maintain regular testing to ensure no coliform presence in your well water.

The safest solution is to install an Ultra Violet Light System for coliform bacteria.

Why use H2O Equipment Company to solve your coliform bacteria problem?

Because we give you honest advice on how to solve your problem. It’s not uncommon for residential well water to have bacteria, especially when the well has been dormant for a while. We will take you step by step through the process.

Don’t let what you can’t see hurt what you can. Let our experts help protect you and your family from harmful coliform bacteria contamination. Contact H2O Equipment Company at 860-267-0110.

water test coliform bacteria