Bacteria are a diverse group of microscopic unicellular organisms that live in soil, water, and on other surfaces. While most kinds of bacteria are harmless, some can cause illness.

Coliform bacteria indicate that your well or spring water contains disease-causing pathogens from animal waste or septic systems. Water testing is the only way to determine if your drinking water is safe.

1. Shock Chlorination

Coliform bacteria are naturally-occurring organisms that occur in water, soil, and on the bodies of animals and humans. They are not harmful to most people and, if found in your well water, simply indicate that some sort of contaminant source may be present. While coliform bacteria in drinking water do not pose a health threat themselves, finding them suggests that other, potentially harmful, fecal coliform bacteria such as E. coli may be in the supply, which can cause food poisoning.

The most common way that coliform bacteria get into well water is through surface runoff during heavy rainfall or during the installation of a new pump. However, a positive coliform bacteria test can also be the result of a one-time contamination event such as a broken well head or faulty plumbing in your home.

While these situations are rare, a positive coliform bacteria test is still an indication that you need to treat your well or spring water to remove any harmful organisms. To correct the problem, you will need to shock chlorinate your water system using a chemical such as chorine.

During the shock chlorination process, it is important to follow all safety procedures outlined in your well owners manual and on the packaging of your specific treatment product. Make sure to wear rubber gloves and protective eyewear when handling any chemicals. You should also take care not to contaminate the inside of your well tank or piping with any dirt or debris, as this can lead to further contamination in the future.

Once the shock chlorination treatment has been completed, retest your well water for total coliform bacteria within a week or two. If the levels are no longer present, you can begin consuming your well water again and you will not need to consider any alternative methods of disinfection.

If coliform bacteria are still present, it is recommended that you contact a professional well contractor to perform a thorough inspection of your well and plumbing to determine the source of the contamination. It is important to identify and address the source of the contaminated water so that it does not return after the shock chlorination treatment.

2. Ultraviolet Light

While most bacteria are harmless, some can cause gastrointestinal upset including diarrhea. These bacteria can also enter the urinary tract and cause a urinary tract infection (UTI) which is painful, often bloody, and causes symptoms such as pelvic pain, discomfort while urinating, and frequent urination. If fecal coliforms or E. coli are present in water it is likely that other disease-causing organisms such as salmonella and listeria are also present.

Coliform bacteria are found naturally in soils, surface water and plants, but most frequently occur as fecal coliform bacteria in the intestines of warm blooded animals and humans. The presence of fecal coliforms in well water is often a warning that other pathogens such as salmonella and listeria are present as well.

Well and spring waters can become contaminated by fecal coliforms if the well was improperly constructed allowing surface water to infiltrate into deep groundwater or if it is located near land uses that contribute sewage, animal waste, and/or septic system contamination to the well water supply. Contaminants can also get into a well water supply if the well head or casing is damaged.

UV sterilization is a safe and effective way to kill coliforms and other pathogens in drinking water. It is an in-line, point of entry water treatment system that can be installed at the water line where it enters your home. UV systems can destroy a wide variety of contaminants, including bacteria, viruses, protozoa, and fungi.

Because coliforms are shielded by dissolved minerals and suspended sediment, pretreatment of the water is necessary to ensure that UV light can reach the bacteria and eliminate them. UV disinfection systems are available with capacities up to several hundred gallons per minute. They work by passing the water through a UV lamp which kills the bacteria. This type of system is easy to maintain, but should be cleaned regularly. The UV system must be in contact with the water for about 15 minutes in order to achieve the best results.

3. Boiling

Coliform bacteria are naturally occurring organisms that are found in water, soil and the bodies of humans and animals. They are known as indicator organisms because they provide an indication that a water supply may contain disease-causing pathogens. The presence of coliform bacteria in your well water does not necessarily mean that drinking the water will make you sick, however, high levels of coliform bacteria could indicate that a contamination pathway exists between your well and a source of coliform bacteria (surface water, septic systems, animal waste, etc).

Most commonly, coliform bacteria are detected by testing for Total Coliform bacteria, a group of bacteria that are common in the environment and usually harmless. However, if the results also show the presence of Fecal Coliform bacteria, which are found in the intestines and faeces of humans and animals, it is likely that environmental pollution has occurred and the threat of more harmful pathogens entering your well water is greater.

The most likely cause of a positive result for fecal coliform bacteria is sewage or animal waste seeping into the groundwater and washing through soil to reach your well. Other common sources of fecal contamination include septic tanks, livestock areas and drain fields. In addition to addressing any possible pollution sources, disinfection of the well and water system is typically recommended after detection of fecal coliform bacteria in a water sample. This may be accomplished through shock chlorination, UV treatment or boiling the water.

Boiling your water to a rolling boil for one minute will destroy any fecal bacteria in the water, and should eliminate any other bacterial or viral contaminants in the water. You can also use a UV light to treat the water and kill any remaining fecal bacteria and viruses.

It is important to test your well water for coliform bacteria regularly, especially if you have young children or elderly people living in your home who are more susceptible to serious and life-threatening illness caused by ingesting contaminated food or drinking water. In addition to regular testing, well owners should maintain a distance between their well and sources of surface water runoff or septic tank, and keep the well structure in good condition to prevent contamination from leaking into the well.

4. Filtering

Coliform bacteria are found naturally in water, soil and the waste of humans and animals. They are considered “indicator organisms” and when found in a drinking water supply, it indicates that there is a possible contamination source. It does not mean that the water is necessarily harmful to drink, but it does indicate that other disease-causing bacteria or protozoa (like dysentery and hepatitis) may also be present in the water. It is not cost-effective to test for each of these independent pathogens individually, so testing for coliform bacteria is done as a more general indicator of the presence of potential pathogens in drinking water.

Most contaminated wells are caused by environmental pollutants, such as surface runoff and sewage spills. While these sources are usually less serious than fecal coliform contamination, they can still cause problems if they get into the groundwater supply. Water treatment systems that rely on filtration are able to remove these contaminants, including coliforms and other potentially dangerous microbes.

Depending on the contaminant, different types of filters will be used. A water filtration system will have porous membranes or adsorption media that can bind chemical pollutants and heavy metals, while also filtering out bacteria and other pathogens. Water treatment filters can be installed at the point of entry for the entire house or at the point of use for select faucets.

Wells that are built close to a septic system or sewage plant are particularly vulnerable to contamination. This is also true of older wells that have not been properly maintained or sealed, and of spring-fed systems and cistern-type water storage systems that do not have an airtight seal in the well cap.

Getting rid of coliform bacteria in well water is essential for your health. While these bacteria are harmless, their presence in your home water is a warning sign that other harmful pathogens may be present in the same water. Some people are more sensitive to these pathogens than others, and children and the elderly are especially susceptible. In addition, bacterial contamination can result in a variety of symptoms, from mild to severe.