Fluorine and Chlorine are halogen gases that are remarkably similar in chemical makeup.
The halogens, both poisonous gases, have been indicted as cancer-causing chemicals.
They are extremely reactive chemically, and thus create free radicals, which in turn, are carcinogenic.
So water filters that remove fluoride are very important.
Surprisingly, many tap filters do not do a very good job of removing fluoride. A very few modern communities use ozone, which is a tri molecular form of oxygen, instead of halogens, to purify their water.
But your community is not statistically likely to be among them. Fluoride, the reduced form of fluorine that is in common use, can leach into water supplies, but was often added in the mistaken idea that it was good for teeth and otherwise harmless.
Water filters that remove fluoride are important to your health. Oddly enough, there is evidence that fluoride causes browning of the teeth through breakdown of the enamel.
But toothpaste that contain high levels of fluoride also contain short-term whiteners, so this is not immediately evident. So, to have healthy teeth instead of cosmetically-enhanced teeth, water filters that remove fluoride are a given. Excessive fluoride can also lead to premature aging.
Fluorine is more toxic than lead and only slightly less toxic than arsenic. It can cause genetic damage and enzyme breakdown. Sarin nerve gas is an organic compound of fluorine. Fluoride is not your friend but water filters that remove fluoride, are.
How do water filters remove fluoride? They can use carbon filters, but it must be a very high quality of filter. The Aquasana system, for instance, uses activated coconut shell charcoal. If you want a water filter that removes fluoride, this would be a brand to get.
This is a very dense form of charcoal that can be highly activated, and can remove forty to sixty percent of fluoride. Other forms of charcoal may not fare as well. Water filters that remove fluoride may not be able to reduce your fluoride-burden to zero, but you can reduce it as much as possible.
It is also preferable to have your dentist do a periodic anti-cavity treatment, rather than ingest fluoride from toothpaste every day. You may not like visiting your dentist, but too much fluoride and you will be visiting your doctor.
Given the above, your question should not be “Do I want a water filter that removes fluoride?” It should be “When do I get one, and what brand removes the most?”