Safety standards for drinking water
The U.S. Environmental Protection Agency (EPA) requires municipal water treatment operators to monitor coliform bacteria levels in the water, with the health standard being zero total coliform. However, private wells are not monitored by federal, state, or local authorities—the responsibility for well water safety lies in the homeowner’s hands. Testing your home’s well water for bacteria is the only reliable way to know if your water is safe, as most of the time you cannot tell by the look, taste, or smell of the water if it contains disease-causing organisms (pathogens).
What are coliform bacteria?
Total coliform bacteria are found in the environment and feces of all warm-blooded animals, including humans. There are many types of coliform bacteria and while most don’t cause illness, their presence in your well water indicates that there could be harmful pathogens in your water supply.
There are three groups of coliform bacteria:
- Total coliform—a large collection of different kinds of bacteria.
- Fecal coliform bacteria—a subgroup of total coliform bacteria.
- E. coli—a subgroup of fecal coliform.
Potential health effects
Water pollution caused by fecal contamination is a serious problem, due to the potential for contracting diseases from pathogens, such as some strain of E. coli. They can cause severe illness, with symptoms including severe diarrhea and abdominal cramps. Children, the elderly, and people with compromised immune systems are the most susceptible.
How do coliform bacteria get into well water?
Coliform bacteria are called "indicator organisms" because their presence indicates a possibility of disease-causing bacteria, such as E. coli, being in the water. A positive coliform bacteria test does not necessarily mean your drinking water is unsafe, but it does mean that something is wrong.
Common sources of coliform contamination of wells
So, how can you spot if coliform bacteria may have contaminated your well water? Look out for the following signs:
- A loose, missing, or defective well cap—seals around wires, pipes, and where the cap meets the casing may be cracked, letting in contaminants.
- Contaminant seepage through the well casing—cracks or holes in the well casing allow water unfiltered by soil to enter the well. This seepage is common in wells made of concrete, clay tile, or brick.
- Contaminants seeping along the outside of the well casing—many older wells were not sealed with grout when they were constructed. If the area around the well casing is flooded, it can force bacteria into the well.
- Well flooding—a common problem for wellheads located below the ground in frost pits that frequently flood during wet weather.
- Standing water next to the well—make sure that runoff water does not pool near your well.
- Recent work on the well, pump, or plumbing system.
- Animal waste entering the water supply or malfunctioning septic systems.
- Contamination of the water supply from pump replacement, drilling, and well repairs.
Testing your well water for coliform bacteria
The best way to determine whether harmful pathogens are present in your well water is by testing for total coliform. Their presence or absence gives a general indication of the sanitary condition of your water supply.
The Health Metric Bacteria Test makes it easy to check your water supply for coliform contamination. The at-home test uses a EPA-approved method for screening well water for the presence of coliform bacteria. Simply fill the jar with water and wait 48 hours. If the water in the jar turns yellow, the test is positive for coliform bacteria. If it remains purple, the results are negative. More information on using the Health Metric bacteria test kit along with helpful testing tips can be found here.
What to do if the test is positive
The Health Metric bacteria test is a “presumptive” test, providing a simple a yes/no result. A positive indicates that your water supply is being contaminated somewhere in the well or plumbing system, so repairs or modifications may be required. In some cases, the source of contamination can only be controlled by an in-home treatment system. A water treatment professional may suggest a chlorine injection or UV disinfection system.
Boiling the water is advised until disinfection and retesting confirms that contamination has been eliminated. If necessary, your water can be tested by a lab to specifically check for the presence of harmful coliform strains.
Test your well at least once a year
The EPA and local water authorities recommend testing your well for bacteria at least once a year. If you’ve had maintenance or repairs made to your well, test to make sure the well has not been accidentally contaminated.
You should also test if:
- There are known problems with well water in your area.
- You have experienced problems near your well, such as flooding and land disturbances.
- You notice a change in water quality such as taste, color, or odor.
- Whenever the well is inundated by flood waters or surface runoff.
For more information on how to test for a safe well water supply, contact us on support@health-metric.com.
Well Water Test Kit—simple and professional testing with no hidden fees
The Health Metric Well Water Test Kit includes a coliform bacteria test plus seven other important water quality parameters to determine the quality of your water. The test kit allows you to test your well water and compare the results to official EPA standards. Find out more.
FAQs
What happens if your well tests positive coliform? ›
What do the Results Mean? If coliform bacteria are present in your drinking water, your risk of contracting a water-borne illness is increased. Although total coliforms can come from sources other than fecal matter, a positive total coliform sample should be considered an indication of pollution in your well.
Can I test my own well water for bacteria? ›You can complete your own well water testing and there is no need to hire a professional or pay a laboratory to do it. Going online, you can find affordable water testing kits: no need to wait days or weeks to find out if your well water is good for drinking or general use.
What is a safe level of coliform in well water? ›Publication No. 4: Bacteria in Private Drinking Water Wells
The Maximum Contaminant Level (MCL) for bacteria in drinking water is zero total coliform colonies per 100 milliliters of water as established by the EPA.
Yes, you can take a shower in water with coliform as long as you do not drink the water. Maintaining the proper levels of bacteria in any water source is vital to your health.
Will shocking a well get rid of coliform? ›When done properly, shock chlorination will kill all the bacteria existing in a well. A recent Penn State study of wells contaminated by coliform bacteria found that shock chlorination and installation of a sanitary well cap successfully removed the bacteria for one year in 15 percent of the wells.
What removes coliform from well water? ›Biological contaminants such as coliform bacteria are most effectively eliminated through chlorine disinfection, filtration, ultraviolet irradiation, and ozonation.
Is it common to have coliform in well water? ›Various types of Coliform live in the soil and even on surfaces in your home, but they do not occur naturally in groundwater. If Coliform bacteria (sometimes reported as Total Coliform) are found in your well water, it is an indication that disease-causing bacteria could get in the same way.
How can I test my well water myself? ›Fill a test container with a water sample, dip a test strip in, swirl the container, and wait a few minutes with the test strip resting in the water sample. Take the strip out of the water and compare the color changes on the test strip to a color chart included in the kit.
How do you remove coliform from water? ›How Do I Remove Coliform Bacteria From My Drinking Water? The water can be treated using chlorine, ultraviolet treatment system or ozone, all of which act to kill or inactivate E. coli. Systems using surface water sources are required to disinfect to ensure that all bacterial contamination is inactivated, such as E.
How many coliforms are OK in drinking water? ›Maximum Acceptable Concentration for Drinking Water = none detectable per 100 mL This means that in order to conform to the guideline: • For every 100 mL of drinking water tested, no total coliforms or E. coli should be detected.
What is the survival time of coliform bacteria in groundwater? ›
Escherichia coli and Streptococcus faecalis survived for more than 42 days.
What are the symptoms of coliform? ›Health effects
Symptoms of waterborne diseases may include gastrointestinal illnesses such as severe diarrhea, nausea, and possibly jaundice as well as associated headaches and fatigue. It is important to note, however, that these symptoms are not associated only with disease-causing organisms in drinking water.
Boiling water kills coliform bacteria, but does not remove nitrate. Do NOT boil water with both coliform and nitrate. It may increase the nitrate level, making the problem worse!
How long can coliform bacteria live? ›Research has shown an incubation period of 2-8 days, while E. coli can remain contagious through fecal matter for up to 9 days. Regular interactions, such as kissing, handshakes, and skin contact will not transfer the bacteria.
How long after shocking a well can you drink the water? ›Once the chlorinated water has reached all the appliances, fixtures and faucets, let the chlorinated water stand in the well and plumbing system for 8 hours. WHILE THE CHLORINE IS IN THE SYSTEM DO NOT DRINK THE WATER.
How much does it cost to treat a well for coliform? ›How Much Does it Cost to Treat Coliform in Well Water? The typical cost for shocking a well varies depending on where you live. Costs can be anywhere from $80 to $200. You can reduce the cost by shocking the well yourself.
How do they fix well with coliform bacteria? ›Treating a Well for Bacteria Contamination
A chlorine solution is the simplest and most effective agent for disinfecting a well, pump, storage tank or piping system. Liquid household bleach is the most commonly available source of chlorine.
Coliform bacteria in a water system are generally either a result of a failure to maintain a “closed” system and/or equipment failure. Visually inspect the system including wells, tanks, chlorinator, etc. Look for areas where soil, leaves, insects, animals, sewage or animal wastes could get into your system.
How often should you chlorinate a well? ›Shock chlorination is recommended: upon completion of a new well or when an unused well is returned to service. if annual water test results indicate the presence of bacteria. if a well system is opened for any installation, repair or maintenance.
How do I test my well water for coliforms? ›Testing your well water for coliform bacteria
The at-home test uses a EPA-approved method for screening well water for the presence of coliform bacteria. Simply fill the jar with water and wait 48 hours. If the water in the jar turns yellow, the test is positive for coliform bacteria.
How do I know my well water is safe? ›
The only way to tell if your drinking water is safe is by having it tested at a certified laboratory. Harmful bacteria, parasites, and viruses are invisible to the naked eye, so water which looks and tastes good may not necessarily be safe to drink.
How do I know if my well water is making me sick? ›Symptoms include diarrhea, vomiting, cramps, nausea, headaches, fever, fatigue, and even death sometimes. Infants, children, elderly people, and people with weakened immune systems are more likely to get sick or die from disease-causing microorganisms in drinking water.
How can I test my water at home without a kit? ›Fill the bottle one-third full, add a few drops of pure liquid soap and shake vigorously for a few seconds. If there is a distinct lack of fluffy bubbles and the water appears cloudy and/or milky, your water is hard.
What happens if you drink water with coliform bacteria? ›Most coliform bacteria are not harmful. However, some can make you sick. A person that has been exposed to these bacteria may have an upset stomach, vomiting, fever, or diarrhea. Children and the elderly are more at risk from these bacteria.
What is a high coliform count? ›When a water test indicates a high “Total Coliform” count, the water may or may not contain illness-causing strains such as E. coli. But, when present, coliform are a strong indicator that your water source has already been or can easily become contaminated with fecal matter, and you should disinfect your water.
What does high coliform count in water indicate? ›The presence of fecal coliform bacteria in aquatic environments indicates that the water has been contaminated with the fecal material of man or other animals.
Can coliform in well water make you sick? ›If total coliforms (E. coli) are in your well water, you may have diarrhea, cramps, nausea, headaches or other symptoms. Infants, young children and people with compromised immune systems are at a higher risk.
What water temperature kills coliform bacteria? ›It is also reported that a 99.999% kill of water borne microorganisms can be achieved at 149°F/65°C in five minutes of exposure.
Is it OK to have coliform in well water? ›Various types of Coliform live in the soil and even on surfaces in your home, but they do not occur naturally in groundwater. If Coliform bacteria (sometimes reported as Total Coliform) are found in your well water, it is an indication that disease-causing bacteria could get in the same way.
What does it mean if coliform is present in well water? ›Fecal coliform bacteria are a sub-group of total coliform bacteria. They appear in great quantities in the intestines and feces of people and animals. The presence of these bacteria indicates that your well water is contaminated with feces or sewage, and it has the potential to cause disease.
How do you fix coliform? ›
How Do I Remove Coliform Bacteria From My Drinking Water? The water can be treated using chlorine, ultraviolet treatment system or ozone, all of which act to kill or inactivate E. coli. Systems using surface water sources are required to disinfect to ensure that all bacterial contamination is inactivated, such as E.
How long does coliform bacteria last? ›coli can remain contagious through fecal matter for up to 9 days. Regular interactions, such as kissing, handshakes, and skin contact will not transfer the bacteria.
How long does coliform last? ›How long does it last? Symptoms usually last 5 to 10 days. People with mild symptoms usually recover on their own without treatment. Antibiotics are not helpful for treating E.