Coliform Bacteria in Well Water: Problems, Testing and Removal

This article will discuss:

  • How Coliform bacteria enter the water?
  • What diseases they can cause?
  • When and how to test your water and interpret test results?
  • How you can remove Coliform bacteria from water?
  • How can you prevent Coliform bacteria contamination?

Before we begin, let’s read some basics about coliform bacteria.

What are coliform bacteria?

Coliform bacteria are a common species of bacteria. They are mostly found in soil, surface water, plants, and the intestines of human beings and warm-blooded animals. A majority of coliform bacteria are harmless, but a few can cause mild to severe diseases. Coliform bacteria in well water are referred to as indicator organisms because their presence in drinking water is an alarm for the disease-causing bacteria in water.

How Coliform Bacteria enter the Well Water?

Coliform bacteria can enter the well water through the following ways.

  • They are washed into the ground by rainwater, melting snow, irrigation channels.
  • From woodlands, pastures, or animal feedlots.
  • From animal waste.
  • Poorly maintained septic system.
  • Damaged well cap and well casing.
  • Unplugged or improperly decommissioned/abandoned well nearby.
  • Wells located in close proximity to the septic system and sewage pipes are at high risk of bacterial contamination. Check your state laws for well site selection.
  • Connecting drinking water pipes to non-drinking sources such as wastewater, laundry, and dishwashers.
  • The aquifer is highly fractured, and bedrock and the gravel deposit do not provide an effective filtration to remove bacteria.

What Diseases can Coliform Bacteria cause?

Common health issues related to coliform bacteria are:

  • Vomiting
  • Fever
  • Diarrhea
  • Nausea and upset stomach
  • Hepatitis
  • Cramps
  • Headaches
  • Fever
  • Body fatigue and lethargy

Testing for Coliform Bacteria

The EPA recommends that all private well owners must test well water annually for coliform bacteria. You must get your well water tested if:

  • You notice a change in the taste, smell, and color of the water.
  • The water appears cloudy after it rains, or the wellhead is flooded.
  • If your family experiences an upset stomach, vomiting, fever, diarrhea, or any of the above symptoms and they won’t go away after taking medicines.
  • Your well is located within 50 feet of a contamination source like a sewage pipe or septic tank.

How to Test?

You can either test your water at home or get it tested from a certified laboratory.

Recommended Home Water Testing Kit: SpringWell’s Water Test Kit

SpringWell’s Water Test Kit

SpringWell’s water testing kit is a reliable home testing kit that you can use to identify 53 different contaminants. The kit is specifically designed for well water and home use. It is easy to use and gives accurate results.

Coliform Bacteria Treatment

Treating coliform bacteria from well water needs you to work on two fronts.

  1. Removal
  2. Prevention


Chlorination of well water

Shock Chlorination – Using chlorine to remove bacteria from well water is one of the most trusted and reliable methods. City water authorities periodically chlorinate water to remove microorganisms. Shock chlorination refers to one-time chlorination and is mostly carried out after flooding or well repair, modification, or when a new well is built. A high chlorine concentration is added to your water, and then the water is tested again after 7 days to confirm that bacteria are no longer found in your water.

Continuous Chlorination – Continuous chlorination is best for wells with recurrent bacterial contamination. It is done using an injector. It is installed after the water leaves the well.

Recommended Chlorine Injector: SpringWell’s Chemical Injection System

SpringWell’s Chemical Injection System

The chemical injection system is best for killing Coliform and iron bacteria. It can also oxidize iron, sulfur, and manganese, which may also be present in well water.

The system is easy to install, plugs in a standard 110V outlet, and adds chlorine controlled by a flow sensor, resulting in consistent and optimal results. All you have to do is add bleach and water to the system periodically. The unit gives better results than ordinary chlorinators in the market because it mixes chlorine and water inside the system. It doesn’t leave pellets in the water.

UV Light – UV purification system is an excellent and 99% successful way to remove coliform bacteria and other microorganisms in water. The UV light affects the DNA in these microorganisms, thus eliminating their ability to multiply or reproduce.

Recommended UV Purification System: SpringWell’s UV Water Purification System

SpringWell’s UV Water Purification System

SpringWell’s UV purification system kills up to 99.9% of bacteria, viruses, and pathogens in well water. The unit is managed by a digital control head. The UV purifier delivers 15 gallons per minute flow rate, which is more than enough for a medium-sized family.

The electronic monitor displays the working status of the unit and when you need to replace the bulb inside the purifier. Moreover, the bulb lasts 12-18 months, depending on water quality and usage.

The only drawback of using a UV system is that it needs a sediment filter before it, as it can’t handle sediment in well water.

Reverse Osmosis – Reverse osmosis or RO filtration is commonly used to purify drinking water. An RO system consists of 4-5 filtration stages, including a sediment filter, carbon filters, RO membrane, UV filters, and a remineralization stage.

The RO membrane removes coliform bacteria and other microorganisms from water. It also removes 99% of contaminants from water, making it fit for drinking and cooking.

Recommended Reverse Osmosis Filter: SpringWell’s Reverse Osmosis Drinking System

SpringWell’s Reverse Osmosis Drinking System

SpringWell’s RO system is a 4-stage water filtration system with sediment, carbon, and RO filters. The best thing about SpringWell’s RO filter is that it can remove heavy metals such as lead, fluoride, and arsenic. The water leaving the filter is 100% pure for drinking and cooking purposes.

The unit has a pressurized tank and a 75-liter daily filtration capacity. Overall, it is a durable and reliable RO system for well water.

Whole House Water Filter – A whole house water filter with a UV purification system is best for people looking to treat water for every point of use. The whole house system is installed where water enters your home. It is also an excellent option to provide better quality water to the next filters/softeners.

Recommended Whole House Water Filter: SpringWell’s Whole House Water Filter System

SpringWell’s Whole House Water Filter System

SpringWell’s whole house well water filter removes common contaminants found in well water. It can remove iron, manganese, sulfur, or a combination of these contaminants. The unit can be easily paired with a SpringWell’s UV Water Purification System to kill coliform bacteria in well water.

The unit is easy to install, lasts at least 10-12 years, and doesn’t require frequent maintenance. It delivers clean, fresh, and great-tasting water.

Boiling – Boiling is recommended when you don’t have any other treatment options. You must boil water for at least 1 minute to kill all the bacteria in water. However, boiling must be used in emergency or for small amount of water as it removes healthy minerals from water.

Iodination – Iodination is recommended by EPA as a short-term or emergency measure to kill bacteria in water. Long term use of iodine is not healthy and can lead to severe side effects from iodine exposure. A lot of campers and hikers use iodine tablets to disinfect drinking water. Iodine adds a particular taste and smell of drinking water.

Ozone – Ozone is a strong oxidant with the potential to kill bacteria and other microorganisms. Ozone is injected into the water with the help of an ozonation injector. Ozone treatment units are very costly as compared to chlorinators and UV light chambers.

Re-testing your Water

Get your water tested after treating the well water to ensure that Coliform bacteria are no longer present in your well water.


You can avoid bacterial contamination by following the tips given below.

  • Regular well inspection for damages to well cap and well casing.
  • Look for corrosion in well pipes, loose wires, or soil settling.
  • Keep the well area clear of debris.
  • Install concrete pads on the side of the well cap.
  • Do not keep possible contamination sources such as fertilizers, pesticides, septic tanks, and feedlots near your well. Maintain at least 50 feet safe distance.
  • Old wells, wells with leaked caps and casing, and wells too close to a septic system, sewage lines, and animal feedlots are more susceptible to bacterial contamination.

Final Words

One should never ignore annual water testing for well water. The hassle and cost of a water test are far less than the suffering from diseases. A water test allows you to make sure that no contaminants are present in your drinking water and helps you install the right treatment unit.


  • Earl Rojo

    Earl Rojo has been a senior mechanic in well drilling and maintenance firms for 3 years. He is from Longview, Texas, and he loves sharing his experience with others. He frequently writes on various well water issues with a special focus on well maintenance and drinking water quality.

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