Fluoride (F+) is a constituent of many minerals. It is commonly added to public drinking water supplies in less enlightened parts of the world ostensibly for the prevention of tooth decay. Cities often maintain a level of 1.5 to 2.5 mg/L, but concentrations of about 5 mg/L are considered damaging to teeth. High levels of fluoride are often found in the waste water of manufacturing facilities where glass and steel are made. The organic fluorine called sodium fluoride is a by-product of aluminum manufacturing and is a main ingredient of rat poisons. Fluoride that results as a toxic waste by-product of aluminum and fertilizer manufacturing is the main source of the fluoride that is added to public water supplies.

The EPA has established an MCL of 4 mg/L for fluoride.

Fluoride is a powerful systemic poison, comparable to lead and arsenic.

Treatment: Fluoride can be reduced by anion exchange. It can also be reduced by filtration through activated alumina but is best removed by reverse osmosis (93 to 95%) and distillation.

Removing Fluoride from Water

Fluoride occurs naturally in some waters, but is frequently added to municipal water supplies because of a widely held belief that it prevents dental caries.

Fluoride is more difficult to remove than most water contaminants. For practical purposes, there are three choices for removing fluoride from drinking water: distillation, reverse osmosis, and filtration through a special fluoride/arsenic reduction medium called activated alumina. Bone char carbon is used in some localities.

Steam distillers remove a high percentage of fluoride, and virtually any good reverse osmosis unit will provide fluoride reduction of 95% or better. Activated alumina, called AAL, removes fluoride well, but requires a relatively large bed and very slow flow rates. Some cartridge makers recommend flow rates in drinking water units of 1/4 gallon per minute for optimum performance.

Because it requires such slow flow rates, AAL is not practical for whole house filtration. In fact, there is no suitable whole house treatment for fluoride removal at the present time. (Whole house reverse osmosis is not a practical solution for most situations.)

Our feeling is that your best choice for whole house filtration is a high quality activated carbon filter. Although activated carbon is not normally recommended for fluoride reduction, it is known that under the right conditions carbon does remove some of the fluoride from tap water. And even if fluoride removal is minimal, carbon filtration makes significant other improvements by removing chlorine, chloramines, the by-products of chlorination, and chemicals in general.

Go here for more specifics on fluoride removal.