Fluoride in Water: Health Effects, Lithuanian Standards, and How to Protect Yourself
Fluoride in water is a naturally occurring element whose concentration determines whether it protects tooth enamel or poses a health risk. In some western and northwestern regions of Lithuania, fluoride levels significantly exceed safe limits, meaning thousands of residents drink water every day that can cause fluorosis or other long-term effects.
This is especially important for families with young children, since an excessive fluoride dose in childhood leaves irreversible damage on developing teeth. Yet many people have no idea what fluoride concentration is actually flowing from their tap.
Below you will find the limits set by WHO and the Lithuanian hygiene standard, the specific problem districts, the effects of fluoride on the body at different doses, and practical ways in which water filtration systems help reduce fluoride levels to a safe range.
What is fluoride and how does it get into drinking water?
Fluorine is a chemical element widely distributed in the Earth's crust. In drinking water it is found in the form of fluorides, i.e. fluoride ions.
Fluorides enter groundwater naturally: water slowly dissolves rocks and minerals such as fluorite and apatite. As a result, groundwater in certain regions naturally has an elevated fluoride concentration.
Tap water in Lithuania is not artificially fluoridated. The elevated fluoride levels found in some areas are purely geological in origin, linked to the composition of local rock formations.
Some countries, such as the USA, Australia and Ireland, artificially fluoridate their water to prevent tooth decay. Most European countries have moved away from this practice, so the fluoride content of their tap water depends solely on natural geological conditions. With this context in mind, it is important to understand which fluoride limits are considered safe.
Fluoride limits in drinking water: WHO recommendations and the Lithuanian hygiene standard
The World Health Organization (WHO) recommends an optimal fluoride concentration in drinking water of 0.5–1.0 mg/l, since this range offers the best protection of tooth enamel against decay. The maximum limit set by WHO is 1.5 mg/l.
The hygiene standard in force in Lithuania, HN 24:2017, sets an identical maximum permissible fluoride concentration of 1.5 mg/l. This limit matches the WHO guidelines and is mandatory for all water suppliers in the country.
Below 0.5 mg/l, fluoride no longer provides meaningful protection for teeth. Above the 1.5 mg/l limit, especially in children, the risk of dental fluorosis increases. An appropriate fluoride concentration must fall within the narrow range between too little and too much.
Any given dose affects more than just the teeth. The effects of fluoride extend to the entire body.
Effects of fluoride on health: benefits and risks
The effect of fluoride on the body depends directly on the dose: an optimal concentration strengthens tooth enamel, while long-term excess harms teeth and bones and may pose other health risks.
Positive effects: decay prevention and enamel strengthening
Fluorides entering the mouth with water become incorporated into tooth enamel and form fluorapatite. This compound is significantly more resistant to acids than natural hydroxyapatite, so enamel withstands acids released by bacteria far better.
WHO confirms that an optimal fluoride concentration in drinking water significantly reduces the risk of tooth decay in both children and adults.
Real-world practice bears this out. In the city of Calgary (Canada), after fluoride was removed from tap water in 2011, children's decay rates rose compared with neighboring Edmonton, where fluoridation remained unchanged. This case is frequently cited as one of the clearest pieces of evidence that fluoride in water directly contributes to dental health.
Negative effects: dental fluorosis, skeletal fluorosis, and other findings
Dental fluorosis shows up as white or brown spots on the enamel. It can only develop in childhood, up to roughly 8 years of age, while permanent teeth are still forming. New dental fluorosis does not develop in adults.
Long-term excessive fluoride intake causes skeletal fluorosis. This condition is characterized by hardening of the bones, joint stiffness and ossification of cartilage, with movement becoming progressively restricted. WHO links skeletal fluorosis to sustained fluoride intake well above the 1.5 mg/l limit.
In addition, recent studies are examining the possible effects of fluoride on the nervous system and thyroid function. The scientific community is still actively researching this question, and no clear consensus has been reached yet.
The risk doesn't come from water alone. Total fluoride intake accumulates from all sources: drinking water, food (tea, fish), and toothpaste. It is important to assess the whole daily dose rather than a single source in isolation. This is especially relevant in Lithuanian regions where the fluoride concentration in water is naturally elevated.
Fluoride levels in water in Lithuania: which regions exceed the limit?
The most significant fluoride problem is concentrated in Western and Northwestern Lithuania. Problem areas include the Kretinga, Kelmė, Akmenė, Mažeikiai, Šiauliai, Klaipėda, Skuodas, Plungė and Telšiai districts.
The highest recorded fluoride concentration in Lithuania reaches 6.52 mg/l in the Kretinga district. This is more than 4 times the permissible 1.5 mg/l limit under HN 24:2017.
Such levels are driven by the region's specific geology: in this area, fluorides dissolve from fluorine-bearing rocks into groundwater more intensively than in other parts of Lithuania, due to slower water turnover and the specific composition of the soil.
Water utilities in problem areas already apply fluoride removal technologies so that the supplied water meets the hygiene standard. However, owners of private wells are responsible for their own water quality, so they are especially advised to regularly test their water quality.
Fluoride and children: what should parents know?
The group at highest risk of fluorosis is children aged 3 to 8. During this period, permanent teeth are still forming and the enamel is especially sensitive to excess fluoride.
Toothpaste choice depends on age:
- For children under 3, a fluoride-free toothpaste or one with a minimal amount is recommended.
- For the 3–6 age group, a toothpaste with a fluoride concentration of up to 250 ppm.
- From age 6, standard toothpaste with 1000–1450 ppm can be used.
For infants living in high-fluoride zones (Kretinga, Kelmė, Akmenė districts), filtered water should be used to prepare formula. And most importantly: parents should assess the total fluoride dose from all sources, not just water. Children also get fluoride from toothpaste, tea and fish, so controlling a single source does not guarantee a safe dose.
How to check and reduce the fluoride level in your water?
First, find out the actual fluoride concentration in your water. Contact your local water utility and request a water quality report, or order a water test at a laboratory. Only by knowing the exact fluoride level can you choose the right filtration solution.
There are three main methods for removing fluoride from water:
- Reverse osmosis filters remove fluoride most effectively, eliminating up to 95% of its concentration.
- Activated alumina filters adsorb fluoride ions and serve as a specialized filter medium.
- Distillation removes fluoride but requires more energy and time.
Standard activated carbon filters do not remove fluoride, so they are not sufficient in problem areas.
Aquafilter, which has worked with certified laboratories for almost three decades, helps you choose the right drinking water systems based on your specific water test results.
Frequently asked questions about fluoride in water
What fluoride level in water is considered safe?
WHO recommends an optimal fluoride concentration of 0.5–1.0 mg/l for dental protection. The Lithuanian hygiene standard HN 24:2017 sets the maximum permissible limit at 1.5 mg/l. A concentration below 0.5 mg/l provides no protection for tooth enamel, while exceeding 1.5 mg/l raises the risk of fluorosis.
Is water artificially fluoridated in Lithuania?
No. Tap water in Lithuania is not artificially fluoridated. The elevated fluoride levels found in some regions, especially Western Lithuania, are of natural geological origin, related to groundwater's contact with fluorine-bearing rocks.
Is fluoridated water dangerous for infants and young children?
Water at a safe concentration is not harmful. However, in high-fluoride zones, filtered water is recommended for preparing infant formula. For children under 8, it is especially important to control the total fluoride dose from all sources, since permanent teeth are still forming and the enamel is sensitive to excess.
How to remove fluoride from water at home?
The most effective method is a reverse osmosis filter, which removes up to 95% of fluoride. Activated alumina filters are also suitable. Standard activated carbon filters do not remove fluoride, so when choosing a drinking water system it is essential to check the filtration technology.
Does fluoride in water cause fluorosis?
Fluorosis is not caused by fluoride in water alone, but by excessive total fluoride intake from all sources: water, food and toothpaste. It only occurs during tooth development in childhood. New dental fluorosis does not develop in adults.
If you want to know exactly how much fluoride is in your drinking water, it is worth starting with a professional water test. The Aquafilter team, with almost three decades of experience, will help you evaluate the results and choose the most suitable solution for your specific water composition.