Many lake property owners are usually worried about the presence of harmful bacteria and how it affects the quality of water in their lakes. And if you’ve ever been to a lake, you’ve likely seen signs warning against swimming due to high levels of coliform bacteria. This is why lake restoration systems remain as important as ever.
But what exactly is coliform bacteria and why is it harmful? Coliform bacteria are a group of rod-shaped microorganisms that are commonly found in the environment. They’re not always harmful but can cause serious illness if ingested or when they come into contact with open wounds. While coliform bacteria are common in lakes, there are ways to control them.
At Clean-Flo, we’ve had many success stories, helping with lake restoration. And in this blog post, we’ll discuss how to identify and control coliform bacteria in lakes. To learn more about these and more, keep reading!

What are coliform bacteria?
Coliform bacteria get their name from the Coli culture test, which is a test used to detect these bacteria in water and other samples. They are a group of rod-shaped microorganisms that are commonly found in the environment.
Generally, coliform bacteria do not cause disease. But the presence of a high level of coliform bacteria is usually an indication that other disease-causing organisms may be present in the lake. While they’re not always harmful, coliform bacteria can cause serious illness if ingested or when they come into contact with open wounds.
Coliform bacteria in lakes can come from a variety of sources, including feces, soil, vegetation, and animal carcasses. They can also be introduced into lakes through stormwater runoff and wastewater discharge. Coliform bacteria can survive in a wide range of environmental conditions, so they can be found in both fresh and saltwater.
What are the causes of coliform in lakes?
The causes of coliform bacteria in lakes vary. Coliform bacteria can come from a variety of sources, including feces, soil, vegetation, and animal carcasses. They can also be introduced into lakes through rainwater runoff and wastewater discharge.
Other common causes of coliform bacteria in lakes include:
· Improperly treated or discharged wastewater
· Bacteria blooms
· Agricultural runoff
· Septic tanks
· Animal waste
· Human feces
Each of these sources can introduce coliform bacteria into lakes, and these bacteria can survive in a wide range of environmental conditions. Since the causes of coliform in lakes are so diverse, it’s important to take steps to control them all.
How to identify coliform bacteria in lakes?
There are a few ways that you can identify coliform bacteria in lakes. Coliform bacteria can be identified through laboratory tests, such as the Coli culture test. This test is used to detect these bacteria in water and other samples.
Another way to identify coliform bacteria is through their physical appearance. Coliform bacteria are rod-shaped and typically have a curved or comma-shaped end. They often group into colonies and can be a light yellow, green, or red color.
Once you’ve identified coliform bacteria in your lake, it’s important to take steps to control them.
How to control coliforms in lakes
If you’re experiencing a coliform bacteria bloom in your lake, it’s important to take steps to control it. The presence of coliform in lakes can be controlled or reduced in a variety of ways. One way to control coliform bacteria is through source control. This means reducing the number of coliform bacteria that enter the lake from other sources.
Sources of coliform bacteria can include feces, soil, vegetation, and animal carcasses. Coliform bacteria can also be introduced into lakes through rainwater runoff and wastewater discharge.
You can reduce the number of coliform bacteria entering your lake by implementing best management practices for agricultural runoff, wastewater treatment, and rainwater management. You can also install fences around animal feeding areas to keep animals away from the lake, and properly dispose of animal carcasses.
Another way to control coliform bacteria is through chemical treatment. Some people use different chemicals to kill coliform bacteria, including chlorine and ozone. Chlorine is the most commonly used chemical for this purpose, and it’s often added to water supplies as a disinfectant.
Coliform bacteria can also be tackled through physical treatments. This involves using methods like filtering or aerating the water to remove the bacteria. Physical treatments are often used in conjunction with chemical treatments. It’s also important to remember that coliform bacteria blooms can recur, so you should continue to monitor your lake for them.
At Clean-Flo, we have diverse superior biological methods of controlling pathogenic bacteria in lakes. For instance, our natural treatment for bacteria reduction in water—through our Continuous Laminar Flow Inversion Oxygenation System—will help you restore your lake to the right condition if it has been contaminated by high levels of bacteria.
How long does coliform live in water?
Coliform can live in water for several days, weeks, or even months. It depends on the environmental conditions, and how much sunlight and oxygen are available. The relationship between coliform presence and oxygen is such that the coliform bacteria bloom is promoted in water with low dissolved oxygen and the coliform bacteria die-off is inhibited in water with high dissolved oxygen. Dissolved oxygen levels are often an indicator of water quality. Coliform bacteria can also die off fairly quickly in cold weather.
The length of time coliform can survive in lakes varies, so it’s important to remember that coliform bacteria blooms can recur, so it’s important to stay vigilant and monitor your lake regularly all year long. Coliform bacteria can have a significant impact on lakes and their ecosystems. It’s important to take steps to control them and keep your lake healthy.

Can I swim in a lake with coliform?
It’s often advisable to avoid swimming in lakes that have coliform bacteria blooms. Coliform bacteria can cause many health problems, including gastroenteritis, eye infections, and skin rashes. Some people are also allergic to coliform bacteria.
If you do choose to swim in a lake with coliform bacteria, it’s important to take precautions. Make sure to shower and wash your clothes immediately after swimming. Also, avoid swallowing any water while swimming. If you experience any symptoms after swimming in a coliform bacteria-containing lake, contact your doctor.
Swimming in contaminated water can lead to a variety of health problems, including gastroenteritis, eye infections, and allergic reactions. It’s best to avoid swimming in Coliform bacteria-containing lakes, but if you do choose to swim, take precautions by showering and washing your clothes immediately after swimming, and avoid swallowing any water. If you experience any symptoms after swimming in a coliform bacteria-containing lake, contact your doctor.
Lake Restoration Experts You Can Trust
Has coliform bacteria taken over your lake, or do you have a lake that needs restoration? For over 50 years, Clean-Flo has been helping to restore lakes across the world. This is because we have the best lake-restoring technology.
Our team of experts can help assess the damage and provide a plan to return your lake to its former glory. Not only do we have the best technology, we provide free cost estimate when you call us.
With our lake restoration system, you can rest assured knowing that your lake will be healthy and beautiful again. We have the experience and knowledge to get the job done right – and we’re passionate about restoring lakes for future generations.
Give us a call today to request a free cost estimate and we’ll be happy to help you.