Quick Answer:
Cyanobacteria occur naturally in lakes, rivers, ponds and other surface waters. Under certain conditions, they can multiply rapidly and form harmful algal blooms. Some cyanobacteria are capable of producing compounds known as cyanotoxins. Public water systems use treatment, monitoring and operational processes to manage these concerns.
For homeowners interested in an additional treatment barrier, the U.S. Environmental Protection Agency identifies technologies including activated carbon and reverse osmosis as potentially applicable to certain cyanotoxins. Effectiveness varies considerably depending on the specific toxin, treatment technology, water conditions and other factors. US EPA
What Are Cyanobacteria?
Cyanobacteria, sometimes called blue-green algae, are naturally found in surface waters.
When conditions such as warm water and abundant nutrients are present, cyanobacteria can multiply rapidly. Some of these blooms are capable of producing cyanotoxins.
That distinction is important:
The presence of cyanobacteria does not, by itself, tell you whether a particular cyanotoxin is present or at what concentration.
EPA maintains separate resources for monitoring, sampling and laboratory analysis of cyanotoxins because identifying cyanobacteria and determining the presence of specific toxins are different questions.
Cyanobacteria vs. Cyanotoxins: What's the Difference?
The easiest way to understand the issue is to separate the organism from the compounds it may produce.
Cyanobacteria are the organisms. They are compounds that certain cyanobacteria can produce.
Some cyanotoxins can exist within cyanobacterial cells, while dissolved toxins may be present outside of cells. This distinction matters during water treatment because different processes are used to address intact cells and dissolved toxins.
EPA specifically cautions that certain treatment processes can rupture cyanobacterial cells and release intracellular toxins into the surrounding water if treatment is not properly managed.
This is one reason drinking-water treatment is more complicated than simply asking whether cyanobacteria are "alive" or "dead."
What About Earthy or Musty-Smelling Water?
Cyanobacterial blooms can also contribute to noticeable taste and odor problems.
According to EPA, harmful algal blooms can create earthy or musty tastes and smells in drinking water. EPA treats these taste-and-odor issues separately from cyanotoxin concerns.
That distinction is particularly important for homeowners. An unusual taste or odor alone does not tell you:
- whether cyanotoxins are present
- which compounds are responsible
- how much of a particular compound is present
- what treatment, if any, is appropriate
Rather than trying to diagnose water based on appearance, taste or smell alone, homeowners should begin with information from their water supplier and appropriate testing when a specific contaminant is a concern.
What Happens Before Municipal Water Reaches Your Faucet?
For homes served by a public water system, the water coming from the faucet is not the same as the untreated water in the lake, reservoir or river supplying the system.
This creates another important distinction:
- Source water is the water entering the treatment process.
- Finished water is the water after treatment.
EPA says conventional drinking-water treatment consisting of coagulation, sedimentation, filtration and chlorination can generally remove intact cyanobacterial cells and low levels of cyanotoxins from source water. Severe bloom events can create additional challenges, which is why public water systems may monitor conditions and adjust treatment accordingly. USA EPA
Homeowners concerned about cyanobacteria should therefore avoid drawing conclusions about their tap water solely from conditions observed in the source water.
Start With the Right Information
If you're concerned about cyanobacteria or cyanotoxins, there are several different questions worth asking.
- What is happening in the source water?
- What is being tested?
- Are tests looking for cyanobacterial cells, cyanobacterial DNA, specific cyanotoxins, or something else?
- What is being found in finished drinking water?
- What information has the public water supplier provided?
EPA maintains resources specifically covering cyanotoxin sampling, detection methods, laboratory analysis, treatment and monitoring. US EPA
The distinction between these questions is also reflected in the background material that prompted this article.
Can Home Water Treatment Provide an Additional Barrier?
Some homeowners are comfortable relying entirely on their public water system. Others choose additional treatment inside their homes for taste, odor or particular water-quality goals.
Neither decision changes the responsibility of a public water system to properly treat and monitor the water it provides. Residential treatment simply provides homeowners another option.
Two technologies frequently discussed in connection with these concerns are activated carbon filtration and reverse osmosis.
Activated Carbon Filtration
Activated carbon is widely used in water treatment, but its performance depends on the application.
EPA identifies both powdered activated carbon (PAC) and granular activated carbon (GAC) in its cyanotoxin treatment guidance.
For cyanotoxins specifically, EPA says GAC effectiveness varies according to factors including the type of carbon, pore size, type of cyanotoxin, natural organic matter in the water and the condition of the carbon. EPA identifies GAC as effective for microcystins and likely effective for several other cyanotoxins, while emphasizing these performance variables. US EPA
For a homeowner, the important takeaway isn't that "carbon removes cyanotoxins." It's that carbon is a treatment technology with different capabilities depending on the equipment, media, contaminant and water conditions.
That is why a treatment professional should understand the homeowner's actual concern before recommending equipment.
Reverse Osmosis
Reverse osmosis, commonly called RO, is a point-of-use treatment technology that uses a semipermeable membrane as part of the treatment process.
EPA identifies reverse osmosis as generally applicable for removal of microcystins and cylindrospermopsin.
EPA also specifically notes that performance depends on the type of cyanotoxin, membrane material, membrane pore-size distribution and incoming water quality, and that additional research is needed to further characterize performance. US EPA
This is an important qualification. It would not be accurate to assume that every RO system removes every cyanotoxin simply because it uses reverse osmosis technology.
Where EcoWater Systems Fit Into the Conversation
Tri-County Water offers EcoWater residential water-treatment equipment, including whole-home filtration and point-of-use reverse osmosis drinking-water systems.
These technologies give homeowners options for adding treatment inside their homes.
However, choosing equipment should start with the water concern, not the product.
If the concern is primarily taste or odor, the appropriate approach may be different from a homeowner specifically concerned about a particular dissolved contaminant.
If reverse osmosis is being considered, homeowners should review the specific system's performance data and certifications rather than relying on a general claim about RO technology.
NSF explains that NSF/ANSI 58 establishes requirements for residential reverse-osmosis drinking-water treatment systems and allows manufacturers to certify specific contaminant-reduction claims. Certification to the standard does not mean that every system is certified for every possible contaminant. NSF
Whole-Home Filtration or Drinking-Water RO?
These aren't necessarily competing solutions because they serve different purposes.
A whole-home treatment system treats water entering the home. Depending on the equipment and media selected, it may be used to address specific water-quality or aesthetic concerns throughout the house.
A point-of-use reverse osmosis system concentrates treatment at a particular location, typically providing treated water for drinking and cooking.
Which approach makes sense depends on what the homeowner wants to accomplish.
Rather than starting with "Which system should I buy?" a better starting question is:
"What am I trying to address in my water?"
Can Tri-County Water Test for Cyanotoxins?
A general in-home water analysis should not be confused with specialized cyanotoxin testing.
EPA provides specific resources for sampling, laboratory analysis and detection methods for cyanotoxins. US EPA
If a homeowner is specifically concerned about a particular cyanotoxin, the appropriate next step may involve reviewing information from the public water supplier or arranging specialized laboratory analysis.
Tri-County Water can help homeowners understand their general water conditions and discuss residential treatment technologies, but a general water test should not be interpreted as a laboratory determination that cyanotoxins are present or absent.
Finding the Right Water Treatment Solution
There is no reason to guess about water treatment. Tri-County Water can help homeowners evaluate their water concerns and explore EcoWater whole-home filtration and reverse osmosis drinking-water options.
That conversation should begin with a simple question:
What do you want to address in your water?
From there, a water treatment professional can explain available technologies, their intended applications and the product information relevant to the systems being considered.
For concerns involving a specific contaminant, ask whether specialized testing is appropriate and request the performance data applicable to the treatment equipment before making a decision.
Understand the concern. Ask the right questions. Find the appropriate solution.
Contact Tri-County Water
Frequently Asked Questions
Are cyanobacteria and cyanotoxins the same thing?
No. Cyanobacteria are organisms. Certain cyanobacteria can produce compounds called cyanotoxins. Finding cyanobacteria does not by itself establish which toxins, if any, are present. US EPA
Does musty or earthy-smelling water mean cyanotoxins are present?
Not by itself. EPA separately identifies taste-and-odor problems associated with harmful algal blooms and cyanotoxin concerns. Testing and water-system information are needed to understand what is actually present. US EPA
Does municipal water treatment address cyanobacteria?
EPA says conventional treatment can generally remove intact cyanobacterial cells and low levels of cyanotoxins from source waters. Severe bloom events may create additional treatment challenges. US EPA
Can activated carbon be used for cyanotoxins?
EPA identifies activated carbon as one treatment technology used for certain cyanotoxins. Effectiveness varies based on the carbon, toxin and water conditions, among other factors. US EPA
Can reverse osmosis be used for cyanotoxins?
EPA identifies reverse osmosis as generally applicable for removal of microcystins and cylindrospermopsin, while noting that performance depends on the toxin, membrane and incoming water quality. US EPA
Does every reverse osmosis system remove the same contaminants?
No. Systems can have different certified contaminant-reduction claims. Homeowners should review the specific manufacturer's performance data and applicable independent certifications. NSF
Should I install a whole-home filter or reverse osmosis system?
That depends on the water concern and treatment goal. Whole-home and point-of-use systems perform different functions, so equipment should be selected based on the specific application.
Can a normal home water test determine whether cyanotoxins are present?
Not necessarily. Cyanotoxin detection involves specific sampling and analytical methods. EPA provides dedicated resources covering cyanotoxin laboratory analysis and detection. US EPA
Start by Understanding Your Water
Water quality concerns can be complicated, especially when cyanobacteria, cyanotoxins, taste and odor issues, and different treatment technologies are discussed together. The best place to start is with reliable information and a clear understanding of what you want to address in your home.
Tri-County Water can help you better understand your water and explore available whole-home filtration and reverse osmosis options. When a specific contaminant is a concern, appropriate testing and product-specific performance information can help guide the conversation.
Ask questions. Understand the technology. Make an informed decision about your water.
