What is Coliform Bacteria?
Coliform bacteria are a group of rod-shaped bacteria found almost everywhere. They live in soils, organic matter, and even on your the human skin.
There are three different types of coliform bacteria that shouldn’t be present in drinking water.
- Total coliform bacteria: They’re pretty common in the environment and can be found in the soil and vegetative matter. They’re also pretty harmless. However, their presence in drinking water might indicate further contamination by other pathogens.
- Fecal coliform bacteria: They live in the intestines of people and animals and can cause illnesses like typhoid fever and dysentery. Moreover, their presence in the water supply indicates contamination by fecal matter that might be bearing other hazardous pathogens like viruses.
- E. coli bacteria: E. coli are a subspecies of fecal coliform bacteria and are also mostly harmless. However, a specific strain that’s known as E. coli O157:H7 is known to cause large-scale outbreaks. Therefore, the presence of E. coli in well water is a serious issue that must be addressed immediately.
How Does Coliform Bacteria Get into Wells?
When constructing a well, the contractor will disinfect and seal off the well to prevent contamination. However, bacteria can make their way into the well in various ways over time:
- Unscreened vents or entry points: All entry points and vents have a screen 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, carrying bacteria to the water.
- Groundwater contamination: Your well relies on groundwater to replenish itself. Leaking septic tanks or sewage spills can contaminate the groundwater, causing bacterial issues.
- Surface water entering the well: After a flood, surface water that carries bacteria can seep into the well if the seal on the well has failed. Moreover, surface water can find its way to the underground water source, bringing various contaminants with it.
The Centers for Disease Control and Prevention (CDC) recommends testing well water for contaminants twice a year. You should also conduct thorough well inspection, checking all vents regularly.
Moreover, you should also make it a habit to examine the well casing that houses the well pump and protects water. The casing should extend at least eighteen inches above ground level to prevent surface water from entering the well, and the wellhead must be sealed to prevent contamination.
Signs of Coliform Bacteria Contamination in Water
There are some signs that indicate bacterial contamination:
- Cloudy Water: 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.
- Discoloration of Water: Some bacteria cause discoloration in the water. If you notice your water turning yellow or brown, there is a possibility that bacteria are present.
- Strange Odors: 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.
- Illness: Of course, the most serious and telling sign that your water may have coliform bacteria is an illness. Consuming bacteria-contaminated water can cause intestinal problems such as vomiting and diarrhea.
According to the Environmental Protection Agency (EPA), no amount of coliform bacteria should be present in drinking water. If you ever experience any symptoms, you should immediately test your water. Fortunately, you can run a test by purchasing a home water kit manufactured explicitly for this purpose or sending a water sample to an EPA-certified lab.
How to Treat Coliform Bacteria in Water
1. Shock Chlorination
Shock chlorination is the most widely used method to cleanse private wells of bacterial contamination. It’s also utilized to disinfect new wells before they are in service.
The process entails pouring chlorine bleach into the well, circulating the treated water through the whole piping system, and flushing it out after 12-24 hours. How much bleach you need to clean the entire system depends on the size of the well. If you want to learn more about the specific aspects of chlorination, you can head to this comprehensive guide by the University of Georgia.
Be wary, though, as this method only disinfects the well and the piping system. So, if the groundwater is contaminated by septic runoff, it won’t be effective, and you’ll be better off with one of the following treatment options.
Moreover, shock treatment is a chemical process, so it’s not bereft of potential hazards. We recommend you hire professional help.
Boiling is an effective way to kill coliform bacteria since heat damages the vital structures of protein-based lifeforms.
To effectively kill all the bacteria in the water, you need to boil it in the full-rolling mode for at least a minute. After boiling, allow it to cool in a refrigerator before use.
The distillation process requires you to boil water in a chamber/container/tank until it’s all gas. Therefore, it’s as effective as boiling in removing bacterial pathogens.
Moreover, distilling can eliminate contaminants like arsenic and fluoride since they can’t hold onto gas molecules. Once the contaminants are removed, the gas is cooled down and returned to the original container as pure water.
Since it’s a very effective method for treating water, it’s also employed by bottled water manufacturers to purify their products. There are also pretty good and affordable countertop distillers. Although their purifying capacity of 1.5 litres per hour might not be ideal for large households, they can provide clean water for small families.
Water treatment filters can be installed at the point-of-entry (POE) for your whole house or point-of-use (POU) for select faucets. They remove contaminants out of the incoming water by porous membranes or adsorption media.
However, not all of them are equally effective against bacteria.
- Activated carbon filters: Although activated carbon can adsorb some chemical pollutants and heavy metals, these filters are mostly microfilters with a 0.1-micron pore size. The CDC claims that 0.1-micron is enough to eliminate E. coli, but it’s not enough against many other bacterial and viral pathogens.
- Ultrafiltration: The filters that utilize ultrafiltration generally have a pore size of 0.01-micron or even less. Therefore, they can easily remove coliform bacteria.
- Nanofiltration: Pore sizes of nano-filters range from 0.008 to 0.01-micron, so they can deal with any bacterial pathogen. However, finding a household nano-filtration unit can be difficult.
- Reverse osmosis (RO): In the reverse osmosis process, the water is pushed through a semipermeable membrane with a pore size of 0.0001-micron. This microscopic pore size makes RO units ideal for removing contaminants, including bacteria.
5. Ultraviolet Sterilization
Subjecting the water to ultraviolet light can effectively kill all the microorganisms. However, the water needs to be pure in the first place for the UV process to work.
Ultraviolet rays need to contact every point in the water to cleanse it. If there are minerals, iron molecules, or even some turbidity in the water, it won’t be an efficient purification method.
Therefore, it’s recommended to pre-filter the water before employing a UV sterilizer. Considering that all the filtration methods listed above are highly effective against coliform bacteria, we can say that a UV sterilizer isn’t very necessary.
How Much Does It Cost to Treat Coliform in Well Water?
- Shock chlorination: The costs of chlorine shock treatment vary depending on where you live, but the range is between $80-$200. Of course, you can reduce the cost by shocking the well yourself.
- Boiling: Boiling is cheap since it only requires a bit of gas or electricity, depending on your heating method.
- Distillation: Countertop distillers can be purchased for less than $200.
- Filtration: Filtration systems can be a little pricey, depending on the type. Typical whole house filtration systems for single-family homes run around $2,000. However, there are many under-the-sink filters that you can purchase for less than $500 as well. These filters may need to be replaced annually, adding to the long-term costs.
- UV sterilizer: A UV filter can cost anywhere between $100-$500. However, it doesn’t work well unless paired with a capable filter.
Frequently Asked Questions
Are Coliform and E. Coli the Same?
E. coli is a subgroup of coliform bacteria. Not all coliform bacteria are E. coli, but all E. coli bacteria are coliform.
Can a Water Filter Remove Coliform?
Water filters can remove coliform bacteria if they have a pore size of 0.1-micron. However, it’s best to opt for independently tested products with the relevant NSF certifications.
Which Filter is More Effective for the Removal of Coliform Bacteria?
Due to the minuscule pore size of their membranes, RO systems are best for removing bacteria. Especially when there’s a UV sterilizer thrown into the mix, there’s no way pathogenic contaminants can end up in your drinking water.
Can You Shower in Water With Coliform Bacteria?
The presence of total coliform bacteria itself doesn’t present a health hazard for most people. However, people should avoid showering in contaminated water if E. coli bacteria or fecal coliforms are present.
Especially infants and elderly who can swallow bathing water and people with open wounds that can get infected should stay away from coliform-contaminated water.
Not all coliform bacteria is harmful, but even the presence of the most harmless strain in your well might indicate fecal contamination or other dangerous pathogens, E. coli. That means you should treat it before it leads to serious health problems.
Shock chlorination is one of the most common well treatment methods, but it’s not a permanent solution. Although boiling and distilling the water might provide clean drinking water for small families and these methods are quite affordable, they’re not ideal for large households.
UV sterilization is a pretty effective process that kills all microorganisms, but it might not be as effective if the water isn’t already filtered. Filtration methods, however, can ensure a continuous supply of bacteria-free water for all households.