Bacteria In Drinking Water (3 Ways To Know)

Drinking contaminated water can be dangerous. Of all possible contaminants, bacteria in water is common and of particular concern. So, how do you know if there is bacteria in your water?

Bacteria in drinking water can be identified using home testing kits, laboratory testing, or by looking for signs of contamination including bad smells, how it looks, foam or bubbles, feels slimy or slippery. Laboratory testing is the most accurate method whereas looking for physical signs of contamination is unreliable.

In this post, we will explore why bacteria in water is problematic, bacteria of greatest concern, how to identify the presence of bacteria, the importance of testing for specific types of bacteria, and the potential consequences of drinking bacteria-contaminated water. We’ll also cover how to test your water, well water and rain water tanks.

How To Detect Bacteria In Water

There are various methods and techniques for detecting bacteria in water, each serving specific purposes and offering different levels of accuracy. From simple at-home tests to sophisticated laboratory procedures and physical signs of contamination, the following are the three main ways you can identify if bacteria are present in water:

1. At-Home Water Testing Kits

At-home water testing kits are user-friendly and provide a convenient way for individuals to gain preliminary insights into their water quality. 

These kits typically come with step-by-step instructions and include test strips or vials that change color in the presence of certain bacteria. 

Some kits require you to collect water samples at home, which are then shipped to advanced laboratories for further testing.

Some other popular home testing kits from Amazon include:

While at-home kits are useful for initial screening, do note that they may not provide a comprehensive analysis of all types of bacteria present in the water. Please also note that many of these kits test for not only bacteria but also several other types of contaminants.

2. Advanced Laboratory Testing Methods

Membrane Filtration

In this method, a water sample is passed through a specialized filter with microscopic pores that trap the bacteria. The filter is then placed on a growth medium that encourages bacterial colonies to form. After incubation, the colonies are counted, and the number of bacteria in the original water sample is estimated. 

Presence/Absence (P/A) Test

The presence/absence test is a qualitative method used to determine whether coliform bacteria, including E. coli, are present in the water sample. In this test, a water sample is added to a specific growth medium that supports the growth of coliform bacteria. If coliform bacteria are present, the medium will produce gas or change color, indicating a positive result. 

Enzyme Substrate Tests

Enzyme substrate tests are based on the detection of specific enzymes produced by certain types of bacteria. For example, the detection of β-galactosidase activity is commonly used to confirm the presence of coliform bacteria in water. 

Polymerase Chain Reaction (PCR)

You may have heard of PCR during the pandemic, but this is actually a powerful tool that can also be used to detect even tiny amounts of bacteria in water. PCR can be used to identify and quantify specific pathogens, such as E. coli or Legionella, providing highly sensitive and specific results.

Flow Cytometry

This technique uses lasers and detectors to measure characteristics of bacteria, such as size and fluorescence. Flow cytometry is particularly valuable for analyzing large volumes of water and providing real-time results.

3. Physical Signs – Use Your Senses!

To determine if water may contain bacteria without testing it, you can use your senses to observe certain signs that might indicate contamination:

Smell

Foul or unusual odors in the water may be an indication of bacterial contamination. If the water smells earthy, musty, or like rotten eggs, it could suggest the presence of bacteria.

Look

Visually inspect the water for cloudiness, discoloration, or the presence of sediment. Murky or discolored water might suggest bacterial activity.

Foam or bubbles

Excessive foam or bubbles in the water might indicate the presence of certain bacteria.

Slimy or slippery feeling

If the water feels slimy or has a slippery texture, it could be due to bacterial growth or biofilm formation in the plumbing system.

Taste

Ok, tasting the water should be your absolute last resort! It’s also not a very reliable method. However, – in an absolute emergency – if you notice a strange or unpleasant taste in the water it is likely contaminated.

It’s important that relying solely on your senses to detect bacteria in water is not a foolproof method. Some harmful bacteria might be present in water even if there are no visible signs.

Proper water testing by a certified laboratory is the most reliable way to confirm the presence of bacteria and other contaminants and ensure water safety. If there are any doubts about the water quality, it is best to have it tested by professional.

Why Is Bacteria In Water A Problem?

Bacteria are microorganisms that exist naturally in various environments, including water sources. While the vast majority of bacteria are harmless or even beneficial to your health, there are still several strains that can pose health risks.

Coliform bacteria, which includes Escherichia coli (E. coli), is one such group of concern.

These bacteria indicate possible fecal contamination and the presence of harmful pathogens, making them crucial indicators of water quality.

Some of the issues you may face as a result of bacteria in your water include:

1. Gastrointestinal Issues

Consuming water contaminated with pathogenic bacteria can result in gastrointestinal problems, such as diarrhea, abdominal cramps, nausea, and vomiting. Although some individuals may experience swift recovery, these symptoms can pose significant risks for certain vulnerable populations, including infants, the elderly, and individuals with compromised immune systems.

2. Waterborne Diseases

Certain bacteria, such as E. coli and Salmonella, have the potential to cause waterborne diseases that go beyond affecting the gastrointestinal system. These diseases can lead to more severe symptoms, such as high fever, dehydration, and in extreme cases, life-threatening complications.

3. Skin and Ear Nose and Throat infections

Even when you don’t drink bacteria contaminated water, just coming into physical contact with it may cause skin problems or ear infections. 

4. Environmental Impact

Apart from the health consequences, bacteria-contaminated water can also negatively impact the environment. When untreated wastewater containing bacteria is discharged into natural water bodies, it can harm aquatic ecosystems, leading to water pollution and ecological imbalance.

Bacteria Of Greatest Concern

Water can harbor a variety of bacteria, but certain specific types are particularly worrisome because of their potential to cause severe health problems. These bacteria act as indicators of water contamination, raising concerns about the possible presence of harmful pathogens. Here are some of the most troubling types of bacteria commonly detected in water sources:

Coliform Bacteria

Coliform bacteria are a group of bacteria that are naturally present in the environment, including soil and vegetation.

The presence of coliform bacteria in water indicates possible fecal contamination, as they are commonly found in the intestines of warm-blooded animals, including humans. 

Escherichia coli (E. coli) is a specific type of coliform bacteria and is of significant concern in water quality testing. The presence of E. coli suggests that water might be contaminated with human or animal waste, and it may also signal the potential presence of harmful pathogens.

Enterococci

Enterococci are a group of bacteria found in the intestines of animals and humans. Like coliform bacteria, their presence in water suggests fecal contamination. 

Enterococci are particularly concerning because they can survive and persist in water for extended periods, indicating prolonged contamination, and also show various levels of resistance to common antibiotics, making them difficult to treat.

Salmonella

Salmonella is a well-known pathogenic bacterium that can cause severe gastrointestinal infections in humans.

Typhoid fever, also known as Enteric fever, and paratyphoid fever are life-threatening illnesses caused by Salmonella Typhi and Salmonella Paratyphi bacteria, respectively.

Worldwide, typhoid fever affects an estimated 11 to 21 million people annually, while paratyphoid fever affects around 5 million people each year.

In the United States, there are approximately 350 cases of typhoid fever and 90 cases of paratyphoid fever reported annually, with most cases linked to travel to regions where these diseases are more prevalent.

Both diseases are most common in areas with poor sanitation and contaminated food or water sources. Transmission occurs through sewage contamination, person-to-person contact, and consuming food or water contaminated with the bacteria.

Vaccination against typhoid fever is available but not for paratyphoid fever.

Salmonella Typhi and Salmonella Paratyphi live exclusively in humans, and animals do not spread these diseases to people.

Globally, these diseases still claim thousands of lives.

Campylobacter

Campylobacter is another common waterborne pathogen responsible for causing gastrointestinal illnesses.

Campylobacter infection, or campylobacteriosis, is caused by Campylobacter bacteria and is the most common bacterial cause of diarrheal illness in the United States. It affects an estimated 1.5 million residents each year.

It is often associated with contaminated water sources, particularly those affected by agricultural runoff or contaminated with animal waste.

Symptoms include diarrhea (often bloody), fever, and stomach cramps, usually starting 2-5 days after infection and lasting about a week. In severe cases, it can lead to complications such as irritable bowel syndrome, temporary paralysis, and arthritis.

Legionella

Legionella is a bacterium that thrives in warm water environments, such as plumbing systems, hot tubs, cooling towers, and even in AC runoff. Inhalation of aerosolized water droplets containing Legionella can lead to Legionnaires’ disease, a severe form of pneumonia.

Vibrio cholerae

Vibrio cholerae is the bacterium responsible for cholera, a severe and potentially deadly diarrheal disease. Cholera outbreaks can occur when contaminated water sources are ingested, leading to rapid transmission of the bacteria.

Pseudomonas aeruginosa

Pseudomonas aeruginosa is a bacterium commonly found in natural water sources, but its presence in drinking water can indicate inadequate treatment and distribution systems. It can lead to skin and ear infections, among others.

Why Only Some Bacteria Are Tested For

Testing for all possible types of bacteria in water would be an exhaustive and costly process. Therefore, water quality tests focus on specific indicator bacteria that signal potential contamination. 

Coliform bacteria, including E. coli, serve as indicators of fecal contamination and the possible presence of pathogens. If these indicator bacteria are detected, it suggests that other harmful microorganisms might also be present in the water.

Consequently, testing for indicator bacteria allows for a more targeted approach to water safety evaluation.

When To Test My Water For Bacteria?

According to the Environmental Protection Agency (EPA), you should consider testing your water in the following situations:

1. You are having recurrent gastrointestinal infections.
2. There are nearby areas of intensive agriculture.
3. You notice a change in taste or smell of your water.
4. The water is not as clear as it used to be.
5. There is someone pregnant in your home, or if you have small babies.

How Often Should Well Owners Test For Bacteria?

For well owners, it is generally recommended to test their well water for bacteria at least once a year. Regular testing is essential to ensure that the water remains safe and free from harmful bacteria. Additionally, well owners should consider testing their water more frequently under the following circumstances:

1. After construction or maintenance: Test the well water for bacteria after the well has been constructed or if any repairs or maintenance work has been done on the well.
2. After flooding or heavy rainfall: If the well has been affected by flooding or heavy rainfall, it is crucial to test the water for bacteria as these events can introduce contaminants.
3. After a change in taste, color, or smell: If there are noticeable changes in the water’s taste, color, or odor, it is advisable to conduct immediate testing to identify potential issues.
4. After a suspected contamination event: If there is a suspicion of contamination from nearby sewage systems, agricultural runoff, or other sources, test the water promptly.
5. During illness outbreaks: If anyone using the well experiences unexplained gastrointestinal illnesses, testing for bacteria should be done to check for potential waterborne pathogens.
6. Before and during pregnancy: Pregnant women may want to test their well water for bacteria, especially if the water is their primary source for drinking and cooking, to protect their health and the health of the baby.

Remember that these recommendations can vary based on local regulations, geological conditions, and specific water usage. It is advisable to consult with local health departments or water testing professionals to determine the appropriate testing frequency for your specific situation. Regular testing and proper maintenance of the well are crucial steps in ensuring a safe and reliable water supply.

How Often Do You Test A Rain Water Tank For Bacteria?

Rainwater tanks (or rain barrels) an provide an environment conducive to bacterial growth due to several factors, and exposure to sunlight is one of them. While sunlight can have some disinfecting effects on water, it may not be sufficient to prevent bacterial growth entirely. The growth of bacteria in rainwater tanks can be influenced by various factors, including:

1. Temperature: Rainwater tanks exposed to sunlight can experience higher temperatures, creating a more favorable environment for bacterial growth. Warmer water temperatures can promote the proliferation of certain bacteria.
2. Nutrient availability: Bacteria require nutrients to grow and multiply. Rainwater can carry organic matter, debris, and pollutants from the roof or gutters into the tank, providing a source of nutrients that can support bacterial growth.
3. Sediment accumulation: If sediment accumulates in the bottom of the tank, it can become a breeding ground for bacteria. Sunlight may not reach the bottom of the tank to have a disinfecting effect in this area.
4. Stagnation: Stagnant water can promote bacterial growth. If rainwater remains relatively undisturbed in the tank, it can create conditions conducive to bacterial proliferation.

To minimize bacterial growth in rainwater tanks, it is essential to implement proper maintenance practices, such as:

• Regularly cleaning the tank to remove sediment and organic matter.
• Using a first-flush diverter to divert the initial dirty rainwater away from the tank.
• Using appropriate filters and screens to prevent debris and contaminants from entering the tank.
• Ensuring the tank is properly sealed to prevent external sources of contamination.

Additionally, some rainwater tanks are made of materials that are designed to inhibit bacterial growth, which can also help in reducing bacterial colonization.

Regular testing of the water for bacteria is advisable, especially if the rainwater is intended for drinking or other domestic uses, to ensure its safety and suitability for the intended purpose.

The recommended testing frequency may vary based on local regulations, tank usage, and factors like extreme weather events or changes in water quality.

Testing at least once a year is advisable for drinking water and non-drinking uses.

Quick Summary

Bacterial contamination in your water can lead to gastrointestinal symptoms, but can also cause other various forms of illnesses. To test for bacteria in your water, you have three options.

First, you can use at-home test kits that will show the presence of certain ‘indicator’ bacteria.

Second, you can collect your water and send it to certified laboratories, which will use more advanced techniques and can detect a larger number of bacteria.

Third, you can look for signs of bacterial contamination including smells, look, foam or bubbles, feel, taste (last resort).

If your at-home kit shows presence of indicator bacteria, you can then consider sending it to a laboratory for further testing and also take steps to address the contamination problem. This might include sterilization and using point of entry (e.g., whole house filter systems) or point of use water filters (e.g., water filter pitchers etc).