Fluoride in Water Filters: Things You Must Know  

Fluoride can have positive effects on health, one of which is the prevention of tooth decay. That’s why water fluoridation has been carried out by governments worldwide as a public health initiative.

As fluoride can naturally occur in some water sources, especially groundwater, fluoridation levels differ between countries. This leaves some people in the concern of ingesting too much fluoride.

So if you’re one of these people, worry no more! In this article, you’ll know everything about fluoride in water filters. Whether it’s actually harmful; and if so, how to filter it from water.

Is Fluoride Really Bad for You? 

Fluoride is one of WHO’s essential medicines’ list, which means that fluoride is actually needed for your body to be in its healthiest form. 

Benefits of Fluoride

As you probably know, fluoridated water is crucial to decrease one of the most common diseases known to humans, dental decay.  Studies say that 51 million school-hours and 164 million work-hours are wasted yearly due to dental-related issues.

Fluoride is known to decrease dental cavities in children by 25-30%, which happens due to the infiltration of fluoride inside the dental structure, consequently making it more resistant to bacteria and acidic insults.

When Does Fluoride Become Harmful?

Like any other chemical material, fluoride effects are dose-dependent. This means that as long as you stay under the recommended dose of 0.7 parts per million, you don’t have to worry about any harmful effects. 

But in some countries, fluoride can naturally reach higher levels without the man-made fluoridation process. India, for example, depends on the fluoride-rich groundwater to supply 80% of the overall rural and urban domestic water supplies. That’s when fluoride’s drawbacks start to appear. 

The Side Effects

The first and most common is fluorosis. Mild cases of fluorosis manifest only as esthetically-unpleasant whitish spots on the patient’s teeth. With no functional mishaps. 

However, severe cases can cause pitting of the enamel and, consequently, compromising the overall strength of teeth.

Additionally, fluoride can do the same to the skeletal system, resulting in altered bone structure and calcified ligaments, which increases the liability to bone fracture.

Fluoride is also linked to GIT, kidney, endocrine and fertility diseases. Luckily though, these side effects aren’t that common.

Which Filters Remove Fluoride? 

Not all types of filters can remove fluoride ions. The widely known activated carbon filters, for example, have little efficacy against fluoride. We’ll see next which ones could do the job.    

But before giving actual buying recommendations, we have to understand some basics about the science behind each type of filter. Don’t worry, though. We won’t get too technical.  

Reverse Osmosis (RO)

Osmosis is a natural phenomenon. Let’s say you have two containers that are separated by a semipermeable membrane. In one of these containers, we’ll put contaminated water, to which we may refer to as highly concentrated water. In the other container, we’ll put pure water, which is low concentrated water. 

Naturally, osmosis states that water flows from areas of low concentration to areas of high concentration, which will result in more contaminated water and, consequently, depletion of pure water. 

And this is where these filters come in handy. They use energy to oppose this phenomenon, that’s why it says “Reverse”. In other words, water now flows from the contaminated container to the pure container. The contaminants can’t follow due to the semipermeable membrane.

What Does It Filter? 

Reverse osmosis can filter metal ions like fluoride, calcium, phosphorous, etc. In addition to some biological contaminants like bacteria, viruses, protozoa, etc. 


If the water contains a high amount of impurities, the semipermeable membrane can get clogged, which affects the cartridge’s life and efficacy. 

What’s in the Market?

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iSpring RCC7P-AK 6-Stage filter has grown to be one of the best selling RO filtration systems. This product comes in under-sink design. 

The first 3 stages are sediment and activated carbon filters, which removes all the large contaminants and most of the heavy metals, thus protecting the other stages from being early clogged by these contaminants.

Then comes the heart of the filter, the 0.0001-micron-wide semipermeable membrane that filters almost 99% of the chemical and biological contaminants. 

Afterward, there’s another activated carbon filter to provide the last check to any sediment that might have escaped the previous stages for some reason.

The last stage is actually what adds a high value to this product. RO membrane sadly can’t differentiate between whether minerals are harmful or beneficial. The filtered water, as a result, has crucially lower beneficial value. 

Through the alkaline remineralization stage, this product remineralizes the water with the healthy ions only, thus you can drink the purest and richest water possible.  

Activated Alumina

Activated alumina is a chemical compound that has a high affinity toward metal ions like fluoride and arsenic. This material is made in a very porous form, in which water penetrates. Metal ions are then adsorbed to the alumina’s surface, leaving water to proceed to the user in a pure form. 

Over time, of course, this material gets saturated with metal ions. Hence you have to change the cartridges from time to time.

What Does It Filter? 

Unlike reverse osmosis, activated alumina only removes metal to which it has an affinity. So biological contaminants aren’t filtered. 


As we mentioned, activated alumina is a porous material. So if the water passing through the filter contains suspended solids, this will ultimately reduce the cartridge’s life and efficacy. Thus, pretreatment with another filter that removes this kind of impurities might be needed.

Moreover, as this type of filter depends on affinity, the water pH level has a direct effect on the quality of the process. The ideal pH for removal of fluoride is between 5 and 6, while arsenic’s is 7. Similarly, pretreatment may be required to obtain the ideal pH level.

What’s in the Market?

There are no good standalone alumina filters that we’d recommend. However, there are alumina-containing cartridges that you can install in any standard 10” filter. 

Home Master CFF25-10 Jr F2 is a cartridge that contains both activated alumina and activated carbon. This allows you to use it in 2-stage and even 1-stage filters. 

The product tests claim it removes up to 93% of the fluoride and 98% of the chlorine, in addition to removing pesticides, herbicides, foul tastes and odors

However, there’s a disadvantage you might want to consider. Due to the porous nature, the water flow rate may decrease drastically when the alumina’s cartridge is used.  


Although it isn’t literally a filter, distillation is one of the most widely used water treatment methods. Simply, a distiller heats the water to its boiling temperature (100°C/212°F), which converts it to steam. Surely, contaminants and non-volatile compounds don’t evaporate, they get left behind. 

The steam then passes through cooling tubes, in which it condenses to water again, and lastly it gets collected in a separate pure container.

What Does It Filter? 

Metallic ions, organic contaminants, suspended/dissolved solids, and some toxic chemical substances are filtered by distillation. 

However, volatile organic compounds, like benzene, can evaporate with steam and get condensed again in the supposedly-pure water. 

What’s in the Market?

With a distillation rate of 1 liter per hour, VEVOR Stainless Steel Water Distiller countertop filter provides a unique service at an affordable cost. 

The process can’t be any simpler. You fill the 4-liter container with tap water, then turn it on and just wait till it finishes and automatically turns off. 

However, in case something went wrong and the distiller didn’t turn off, this product is equipped with a safety fuse-like feature. The circuit automatically disconnects when the temperature rises above 160°C/320°F.

Frequently Asked َQuestions

Does my country fluoride water?

Fluoridation differs between countries. So the best way to know whether your water is fluoridated is by asking your local water utility provider.

Do faucet and refrigerator purifiers remove fluoride?

Sadly, no. These filters usually use either sediment or activated carbon filters. As established, these filters have little to no efficacy toward fluoride.

What are the other sources of fluoride?

The main source is dental products; over 95% of these products contain fluoride. Processed food and beverages are the next big source, this includes sodas, beer, cereal, etc.

Other minor sources include tea, some pharmaceuticals, and pesticides.

To Sum Up   

Fluoride is actually beneficial, but only when supplied in the right amount. 

So it’s your call. If you live in a place where you ingest high levels of fluoride, you should use fluoride in water filters. If you live in an area that periodically measures the fluoride levels to make sure they’re within limits, then don’t bother.

We’d generally go with a reverse osmosis filter. It does the main task of filtering fluoride in addition to multiple other contaminants. Compared to the other systems, we think it has the best efficacy and the higher water output volume. 

If you don’t have a high water demand, particularly if you live alone or with a small family, then distillation will be your perfect choice.

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