Cysts in Your Water – Should You Be Worried?

What happens when parasitic cysts contaminate a water supply?

You may remember when NBC shut down production of Ultimate Slip N’ Slide due to a Giardia outbreak. While that situation made headlines, it highlights a much more common concern. Cysts in drinking water can affect homes across the country, especially those using well water.

So what exactly are cysts in water, and should you be concerned?

Cysts in water are microscopic parasites and microorganisms that can cause illness when ingested. These fall into a broader category known as waterborne parasites.

Unlike many bacteria, cyst-forming organisms have a protective outer shell. This allows them to survive:

Because of this, they can remain in water supplies if not properly treated.

While cysts are a problem that can affect anyone and everyone, people who rely on wells should be more concerned. Well water, which is untreated and comes from underground aquifers, is used by about 15% of the United States.

So, how do they get into your wells? Well, these parasites and bacteria can enter your well by surface water infiltrating the well. This can happen with heavy rains, flooding of rivers, and more. While the construction of your well plays a big part in how cysts may get in, and shallower wells are often more susceptible, even the most efficiently constructed wells can allow the microorganisms to enter.

The most common type of cyst is Giardia. According to the CDC, Giardia is a tiny parasite that is found in feces-ridden liquid that comes from infected individuals or animals. According to a report from Penn State University, “Studies showed that the outbreaks occurred in communities with inadequate chlorination systems, improperly operated and maintained filtration equipment, and even unfiltered water supplies.”

The germs from the parasite can be spread from person to person or through ingesting contaminated water. Ingesting Giardia results in giardiasis, which is commonly known as “Beaver Fever,” a diarrheal disease. Why is it called “Beaver Fever?” The disease is commonly called this because beavers typically contaminate the water with their feces, and humans then drink the contaminant.

The second most common type is Cryptosporidium. Like Giardia, Crypto is a small parasite found in water that has been contaminated with feces from infected individuals or animals. The parasite is very resistant to chlorine-based disinfectants and has a protective outer shell which allows it to survive outside the body for long period of time.

Cysts such as Giardia and Cryptosporidium are not something you can see, taste, or smell in your water. In many cases, they are only discovered after someone in the household begins experiencing symptoms, which can delay proper treatment and expose others to the same risk.

Testing is especially important if:

Many people do not realize their water is contaminated until symptoms appear.

Common symptoms include:

Symptoms can appear days after exposure and may last for weeks if untreated.

Boiling water can kill cysts like Giardia and Cryptosporidium, but only as a short-term solution. It can be time consuming and is not practical for everyday use across your entire home.

For long-term protection, more advanced treatment methods are recommended:

UV systems use ultraviolet light to neutralize microorganisms before they reach your tap. This method is effective against parasites, but performance depends on proper system sizing and water quality. High hardness, iron, or sediment can reduce effectiveness, which is why pre-treatment is often required.

Chlorination can reduce certain bacteria and microorganisms when applied correctly with proper contact time. However, it is less effective against tougher cysts like Cryptosporidium, which are resistant to standard chlorine levels.

Distillation removes contaminants by heating water and collecting the purified vapor. While effective, it is typically more expensive and requires ongoing maintenance, making it less common for whole-home use.

Reverse osmosis systems are one of the most reliable solutions for cyst removal. These systems use a semi-permeable membrane to physically separate contaminants from water at a microscopic level.

They are highly effective at removing:

This makes reverse osmosis an ideal solution for safe, high-quality drinking water.

While Giardia and Crypto are not the only types of bacteria homeowners deal with, they are the most common. Reverse osmosis systems are a great way to filter out ANY cyst. For more information on renting or purchasing a reverse osmosis system, click here.

Before choosing a treatment solution, it is important to understand what is actually in your water.

Cysts and other contaminants cannot be detected by taste, smell, or appearance. The most effective way to identify them is through a professional water test.

A Culligan water test provides a detailed analysis of your water quality, identification of potential contaminants like cysts, and expert recommendations based on your specific water conditions.

From there, a Culligan specialist can recommend the right combination of filtration and purification systems, whether that includes reverse osmosis, UV treatment, or a whole-house solution.

If you want peace of mind about your water, scheduling a professional test is the best first step.