Frequently-asked questions

FAQ on Fluoride and Water Fluoridation

1. What is fluoride?
Fluoride is a natural mineral found in soil, fresh water, sea water, plants and many foods. It is used by the body to strengthen teeth and bones.

2. What is water fluoridation?
Water fluoridation is the adjustment of the natural concentration of fluoride in drinking water to the optimal recommended level for the prevention of dental caries (tooth decay).

There is no chemical difference between fluoride present naturally and that which is added to the water supply. The fluoride is added to water supplies in a controlled way, using only amounts scientifically shown to prevent tooth decay without any adverse effects to human health.

3. How much fluoride is in drinking water in the Republic of Ireland?
As of July 1st 2007, the level of fluoride in drinking water in Ireland has been set at between 0.6-0.8ppm. PPM means parts per million and is equivalent to milligrams per litre. This level of fluoride is deemed optimal for protecting the oral health of all age groups.

4. How does fluoride prevent tooth decay?
Tooth decay develops when sugar-containing foods are broken down by bacteria in the mouth, resulting in acid on the tooth surface. This removes minerals from the tooth enamel and can lead to dental caries. Fluoride at an optimal level in the water supply provides the ideal, constant "repair kit" for teeth, making them more resistant to tooth decay in people of all ages, including the young and the elderly.

5. What are the benefits of water fluoridation?
Water fluoridation is the safest and most cost effective method of providing the entire Irish population access to the benefits of fluoride.
Tooth decay has a significant impact on health and wellbeing, and results in high costs to both the individual and the State. It is largely preventable, and therefore a high priority for oral health promotion.

Fluoride strengthens the teeth, strong teeth result in fewer fillings, fewer extractions, fewer visits to the dentist and lower dental bills. To date, there has been a highly significant reduction in the proportions of decayed, missing and filled teeth of people living in areas supplied by fluoridated drinking water in Ireland when compared to those in non-fluoridated areas. It is estimated that, if water fluoridation stopped, the nation's dental health would deteriorate over time to the point where the average five-year old could expect to have 4 to 5 more decayed, missing or filled teeth.

6. Is it safe to drink water with fluoride?
Yes. Drinking fluoridated water with the correct amount of fluoride in the water is not harmful to human health.
Many organisations around the world, including the World Health Organisation, support water fluoridation. At its sixtieth World Health Assembly it explicitly recommended that "for those countries without access to optimal levels of fluoride, and which have not yet established systematic fluoridation programmes, to consider the development and implementation of fluoridation programmes, giving priority to equitable strategies such as the automatic administration of fluoride, for example, in drinking-water, salt or milk, and to the provision of affordable fluoride toothpaste;"
The US Centres for Disease Control and Prevention rated fluoridation one of the 10 most important public health achievements of the twentieth century.

In 2007, after a review of all published information and claims on potential adverse effects, the National Health and Medical Research Council (Australia) concluded that water fluoridation was safe and effective.

A major review was conducted by the European Union in 2011. The EU's Scientific Committee on Health and Environmental Risks (SCHER) similarly was unable to conclude that water fluoridation posed any risks to human health or to the environment

7. I already use toothpaste with fluoride added - why do I need fluoride in the water as well?
Ireland is amongst the worst countries in Europe for high frequency consumption of sweets and confectionery by children and adolescents, therefore the use of fluoridated toothpastes alone is insufficient to prevent tooth decay.

8. Will there be any harmful chemicals in the water as a result of fluoridation?
No. The compounds most commonly used for fluoridating water dissolve completely in water. Only high quality chemicals are used in fluoridating water supplies.

Fluoride is not toxic in the concentrations added to the water. Many substances that we use everyday are beneficial in small amounts, but may be harmful in large amounts, an example is salt. Only very small amounts of fluoride are added to the water.

9. Will I be able to smell or taste the fluoride?
No. Fluoridated water does not smell or taste different to non-fluoridated water.

10. What additives are used to fluoridate Irish drinking water?
Fluoride may be added to public water supplies either in the form of hydrofluosilicic acid complying with the specification for that substance in Schedule 1 to the Fluoridation of Water Supplies Regulations 2007 (SI 42 OF 2007), or in such other form as may be approved by the Minister of Health.

The fluoride currently used is sourced as a primary product; it is mined directly from a raw material source, the mineral fluorospar as calcium fluoride (CaF2). It then goes through a purification process to conform to tightly controlled specifications under the requirements of CEN Standard I.S.EN 12175:2001 to produce Hydrofluosilicic Acid (HFSA), specifically used as the mineral additive, fluoride, to water.

11. Is hydrofluosilicic acid a waste product from the fertilizer industry?
No. The consumer is frequently misinformed on this matter. It is sourced as a primary product as described in Question 10 above.

Representatives of The Irish Expert Body on Fluorides and Health conducted a site visit to Derivados del Fluor in Spain to see and assess the process of hydrofluosilicic acid extraction and its production processes, and the systems and controls in place to ensure the consistency, purity and safety of the product as supplied for use in fluoridation of drinking water in Ireland. The Expert Body was satisfied that production is in compliance with quality, environmental and safety systems and procedures in place and that Derivados del Fluor strives to ensure that these systems and procedures are maintained and continuously reviewed.

12. Who regulates drinking water additives in Ireland?
The Health Service Executive (HSE) is ultimately responsible for the fluoridation of water supplies. However, as the overall functions of sourcing, treatment and distribution of water for drinking rest with the Water Service Authorities (county and city councils); these bodies undertake fluoridation on an agency basis.

The Expert Body has developed a detailed Code of Practice on the fluoridation of drinking water to ensure quality assurance across the delivery of water fluoridation. This Code sets standards and governs all quality systems and practices required for fluoride provision from storage, dosage, safety and technical aspects through to practical logistics.

13. Is fluoridated water toxic?
No, fluoride at the concentrations found in optimally fluoridated drinking water is not toxic.

Waters with high levels of fluoride content are mostly found at the foot of high mountains and in areas where the sea has made geological deposits. Known fluoride belts on land include: one that stretches from Syria through Jordan, Egypt, Libya, Algeria, Sudan and Kenya, and another that stretches from Turkey through Iraq, Iran, Afghanistan, India, northern Thailand and China. There are similar belts in the Americas and Japan. In these areas fluorosis has been reported at levels of up to 20ppm F and chronic fluoride toxicity may develop after many years exposure. High levels of naturally occurring fluoride are not found in public water supplies in Ireland.

14. Is the fluoride concentration in drinking water measured regularly?
Yes. The Regulations require that a daily test is carried out at the water treatment plants by the Water Service Authorities personnel. Monthly fluoride testing of fluoridated supplies is carried out by the Health Service Executive in accordance with the requirements of the Health (Fluoridation of Water Supplies) Act, 1960.

Testing is also carried out on behalf of the Environmental Protection Agency to determine compliance with the Drinking Water Regulations, which also require monitoring of fluoride levels in water supplies.

15. Who carries out the measurements made?
The daily testing is carried out by Water Service Authorities personnel that are trained in the use of the electronic measuring equipment. An increasing number of water services authorities have their own laboratory facilities, with appropriately qualified staff and equipment, which undertake regular fluoride analysis complementary to the statutory monthly sampling carried out by the Health Service Executive.

The monthly testing is carried out by the Public Analysts' Laboratories which are independently accredited by the Irish National Accreditation Board (INAB).

16. What becomes of the results of analysis?
If a test result at a water treatment plant is outside the range specified by Statutory Instrument No 42 of 2007, prompt adjustments are made to the dosing equipment and a new test carried out to ensure that it is within specification.

The analytical results are sent from the Public Analyst's Laboratory to the HSE or Water Services Authority which had the tests carried out. Should there be fluoride values which are either too high or too low (i.e. outside the range 0.6-0.8 milligrams/litre, (as required by Statutory Instrument No 42 of 2007 Fluoridation of Water Supplies Regulations 2007), notification will be sent to those responsible for the fluoridation of the supply in question, stating that adjustment of the dosage is required promptly.

Each Water Services Authority must return complete analytical data (for a range of parameters, including fluoride) to the Environmental Protection Agency which has the statutory function of preparing and publishing an annual report on the quality of drinking water in Ireland.
While the complete analytical data are not published in the EPA reports for practical reasons, there is complete reporting of each value for each parameter for every supply which is higher (by even the smallest amount) than the permitted limit. Thus the full details of all fluoride values in excess of the limit allowed are a matter of public record.

17. What controls are there in place for fluoride in drinking water?
The permissible concentrations of fluoride in drinking waters are governed at both national and European Union level. Under the provisions of Statutory Instrument No 42 of 2007 Fluoridation of Water Supplies Regulations 2007 the concentrations of fluoride in fluoridated public water supplies must be in the range 0.6-0.8 milligrams/litre. The EU Directive, COUNCIL DIRECTIVE 98/83/EC of 3 November 1998 on the quality of water intended for human consumption, specifies that the level should not exceed 1.5 milligrams fluoride /litre of water. The Irish target level of 0.7ppm fluoride is less than half the maximum permitted by the EU.

18. Is fluoride corrosive?
Raw undiluted hydrofluosilicic acid is very corrosive and is a strong acid but once this fluoride additive, hydrofluosilicic acid is added to drinking water at the optimal levels it dissociates completely releasing fluorides ions into the water and it is no longer corrosive.
Water fluoridation has no impact on the acidity or pH of drinking water and does not cause lead or copper to leach out of water pipes.

19. Is water fluoridation "mass medication"?
No, it is simply the adjustment of a naturally occurring element found in water in order to prevent dental decay. Fluoridation can be likened to adding vitamin D to milk or folic acid to cereals. Fluoridation is considered one of the most important and successful public health measures of the twentieth century.

The issue of the constitutionality of water fluoridation was determined in Ryan v Attorney General in 1963. Although this issue could be revisited in the courts, as of now the policy of water fluoridation is certainly constitutional. See pp 199-226 of the Report of the Forum on Fluoridation (2002) for a full discussion of the legalities of water fluoridation.

The "mass medication" argument is also dealt with at length in the report of the Forum on Fluoridation pp 227-238, and more recently in the United Kingdom, by the Nuffield Council on Bioethics (2007), particularly chapters 1, 2, 3 and 7. In summary, the consensus from these documents and from the various legal judgments particularly in the United States, seems to be that the "mass medication" argument fails in the case of water fluoridation for a number of reasons but mainly because of the greater common good arising from decreased dental disease.

Neither is hyrofluosilicic acid considered to be a medicine as outlined below

"The Health Products Regulatory Authority (HPRA), formerly the Irish Medicines Board, is the competent authority for the licensing of human and veterinary medicines and medical devices in Ireland. Its role is to protect and enhance public and animal health through ensuring the quality, safety and efficacy of medicinal products available on the Irish market. Companies wishing to place medicinal products onto the Irish market must apply to do so to the HPRA. Such applications are then assessed and only approved where the required standards of quality, safety and efficacy are met, in line with the requirements of European [Council Directive 2001/83/EC, as amended] and associated national legislation. This legislation addresses the need for licensing of medicinal products for human use but does not address the licensing of individual substances, such as fluoride.

The HPRA considers that neither drinking water itself nor the fluoride added to drinking water in the form of fluoride salts or silica fluoride, as defined in the Health (Fluoridation of Water Supplies) Act 1960, should be categorised as medicinal products requiring marketing authorisations. Drinking water is regulated by the EC Regulation 178/2002 which specifies that water, when it comes out of the tap (point of compliance) is defined as a food or foodstuff unless it is otherwise defined as a medicinal product. The HPRA considers that the fluoridation of drinking water should be seen as a measure consistent with general public health management.

Since fluoridation is provided for by the aforementioned legislation, it is clearly not unlawful.

20. Can the consistent use of bottled water result in individuals missing the benefits of optimally fluoridated drinking water?
Yes, the majority of bottled waters for sale in Ireland do not contain optimal levels (0.6 - 0.8ppm) of fluoride for the prevention of tooth decay.

21. Is fluoridated tap water safe for use in infant formula?
Yes, fluoridated drinking water has been shown to be safe for use in preparing infant formula. Currently there is no significant evidence of any adverse effects to the health of infants consuming infant formula made up with tap water which has been fluoridated at current statutory levels in Ireland.

It is not recommended that people switch from using tap water to bottled water to make up infant formula.

22. What are the effects of water fluoridation on general health?
There are no known side effects of optimal water fluoridation other than mild dental fluorosis, and this has been known since the 1930's.
A number of other claims have been made in various media in relation to water fluoridation and potential health issues. The Forum on Fluoridation Report (2002) considered these issues and found there was no evidence at that time of any negative health effects. "The best available and most reliable scientific evidence indicates, that at the maximum permitted level of fluoride in drinking water at 1 part per million, human health is not adversely affected" (Forum on Fluoridation, 2002)

A review of evidence on the impact of water fluoridation at its current level on the health of the population was conducted by the Health Research Board (HRB) on behalf of the Department of Health and published in 2015. As part of this review studies from other countries were considered. The HRB has found no definitive evidence that community water fluoridation is associated with negative health effects.

The Irish Expert Body on Fluorides and Health continuously reviews any new and emerging issues in relation to water fluoridation. There continues to be overwhelming evidence that water fluoridation significantly benefits dental health and through this, benefits overall health and that fluoridation is safe and effective.

23. What is dental fluorosis?
Dental fluorosis is a cosmetic or aesthetic condition which refers to the way teeth look; it is not considered to be an adverse health effect. At the levels at which fluoride is present in Ireland's water supplies (0.6 - 0.8ppm) any occurrence of dental fluorosis is very mild or mild and in most cases only detectable by a dentist as faint white flecks on the surface of teeth. Not all enamel defects are caused by drinking fluoridated water.

In the majority of cases dental fluorosis generally does not require any treatment but anyone who has any concerns in this regard should consult their dentist.

This is in contrast to the treatment of tooth decay which may on occasion involve the use of general anaesthesia and hospitalisation. Furthermore, non-treatment of dental fluorosis has no health consequences, whereas non-treatment of tooth decay can lead to pain, trauma, disfigurement, loss of teeth and function, problems with nutrition and growth, work/school absenteeism and significant financial and social cost.

24. Is Ireland the only country which fluoridates drinking water?
No. Many countries have water fluoridation schemes, including the United States, Canada, the United Kingdom, Spain, Australia and New Zealand. Water fluoridation is less common in Europe, where fluoridated salt is often available as an alternative, although some populations are supplied with naturally fluoridated public water.

It should be noted that water fluoridation is on the increase worldwide. The Japanese Government in 2000 endorsed water fluoridation as an appropriate means of reducing tooth decay rates, reversing its previous stance against water fluoridation policy.

25. What is the cost of water fluoridation?
In Ireland, approx €3.9m (2014) is spent on water fluoridation which contributes to the reduction of the burden of oral disease. The lifetime cost per person is around €1 per annum.

Ceasing water fluoridation without putting in place an alternative programme to combat tooth decay would be extremely costly. Fluoridation is known to decrease dental decay substantially. The Fluoride and Caring for Children's Teeth (FACCT) survey, a University College Cork-led research project undertaken in 2014 and 2015 shows that children living in fluoridated areas have fewer caries than those who do not. Ceasing water fluoridation would lead not only to the additional financial burden of treating tooth decay but to social costs, as tooth decay can lead to pain and trauma, as well as work or school absenteeism.