Council Services

  • Civic Administration Building
    Church Street, Dubbo, NSW, 2830
  • Office hours:
    9am to 5pm, Monday to Friday
  • Mailing address:
    PO Box 81, Dubbo, NSW, 2830
  • Telephone: (02) 6801 4000
  • Fax: (02) 6801 4259
  • Email: Email us today

Fluoridation of drinking water

Why Fluoridate?

The NSW Department of Health (DoH) encourages water supply authorities to fluoridate their water supplies in order to protect the public’s teeth and reduce tooth decay.

Dubbo City Council adds fluoride to its drinking water raising the level of fluoride naturally occurring in the water to a level that is known to reduce the incidence of dental caries (or cavities).

Why is dental decay a problem?

Dental health is fundamental to one's overall health. A healthy mouth enables a person to eat, speak and socialise without pain or discomfort. Dental decay is the most common health problem of any type in Australia. 

Dental Decay and Fluoride

Dental decay (also called dental caries) is a cavity in a tooth caused by bacterial acids. These acids are produced when bacteria in the mouth break down sugar-containing foods. The acid removes calcium and phosphates from the tooth structure, resulting in cavities in the tooth.

Fluoride can limit the amount of acid produced, and can also repair damage before it becomes permanent. A constant supply of a low level fluoride in the mouth is best for this. In this way, fluoride in the water supply acts like a constant "repair kit" for teeth.

How long has NSW had water fluoridation?

Fluoride has been added to most water supplies in NSW, commencing with Yass in 1956. In NSW alone there are more than 50 years experience proving the effectiveness and safety of water fluoridation. Most Australians have had water fluoridation for 25-50 years. NSW has one of the highest levels of water fluoridation, approximately 95% of the population has access to fluoridated water.

When was Dubbo’s water supply first fluoridated?

Dubbo City Council started fluoridating town water back in September 1984. Powdered Fluoride was used, sodium silico fluoride, until 24 January 2006. Dosing of fluoride stopped between the dates of 24/1/2006 to 15/1/2008 due to the replacement of the old dosing plant and construction of the new fluoride dosing plant as part of the John Gilbert Water Treatment Plant upgrade works.

The new fluoride dosing equipment uses a liquid called hydrofluosilicic acid. This change was driven from a consideration that it was a safer chemical to transfer and dose as the operators didn’t have to come in contact with it like the powder. Council continues to use this type of fluoride.

How much does it cost?

The annual cost of fluoridation is $60,000. There are over 40,595 water customers and so the average cost of this health measure is only $1.48 per person per year.

How much is used?

The National Health and Medical Research Council (NHMRC) which formulates drinking water standards and policies throughout Australia, recommends that the concentration of fluoride in drinking water should be between a minimum of 0.5 milligrams/litre (mg/l) and a maximum of 1.7 mg/l, depending on the temperature. For Dubbo’s climate a figure of 1.0 mg/l is recommended. The unit of mg/l is equivalent to parts per million (ppm).

The raw water used for the city’s supply is sourced from bores which has a naturally occurring fluoride level of 0.2 – 0.3 mg/l, and Macquarie River water which has a naturally occurring fluoride level of 0.15 – 0.25 mg/l.

Water from the two sources is combined in the tank at the head of the water treatment plant. The water is then treated and fluoride added to raise the concentration of fluoride to 1.0 mg/l in the treated water supplied to customers.

How safe is it?

A fluoride concentration of up to 2.5 mg/l will not cause any ill effects. As a matter of interest, seawater has a fluoride level of 2.0 mg/l and so fish, or shellfish, have this level of fluoride or higher. A cup of tea has a typical fluoride concentration of about 10 mg/l. If an exceptionally elevated fluoride dosage of 4.0 mg/l or 400% of the recommended dosage were to occur in drinking water for extended periods, there is some evidence that adverse effects may occur, such as cosmetic mottling of tooth enamel.

The fluoride dosing system at the John Gilbert Water Treatment Plant has been designed to prevent any dosage higher than the recommended level, in accordance with the Code of Practice for the Fluoridation of Public Water Supplies. 

The fluoridation at the Water Treatment Plant is strictly controlled with staff having specialised training and the system under the supervision of the Department of Health (DoH).

Who benefits from water fluoridation?

Australia has relied on community water fluoridation as its main model of delivering optimal fluoride. This provides universal dental decay and preventative benefit to all individuals regardless of age, gender and socio-economic status.

Is water fluoridation NSW policy?

It is NSW Health policy to fluoridate water in NSW as it remains an effective, efficient, socially equitable and safe approach to prevention of cavities in Australia.

What is the evidence for water fluoridation?

An overwhelming weight of scientific evidence supports community water fluoridation as a safe and effective measure in the prevention of dental decay. It has been endorsed by numerous organisations, including the World Health Organisation and the National Health and Medical Research Council.

Water fluoridation has been described by the US Centre for Disease Control and Prevention as one of the top ten public health achievements of the twentieth century.

Testing of fluoride

Comprehensive sampling and testing for fluoride is undertaken. The raw water is sampled during various treatment processes and when fully treated. Weekly sampling at different locations within the city ensures that the fluoride level within the reticulated water system stays within the prescribed range. In addition, each month a sample is taken and forwarded to the NSW Department of Health (DoH) laboratory in Lidcombe for testing. The results of these tests confirm the accuracy of the routine testing undertaken in Dubbo. Detailed operation logs and test results are forwarded each month to the Department of Health for their review.


What safety measures are used?
In keeping with the NSW DoH Code of Practice for the fluoridation of public water supplies Council has the following safety barriers in place:

  1. The bulk storage tank externally sited is not directly connected to the dosing/metering pump. 
  2. A 1,000 litre litre daily use tank has to be topped up via a pump from the bulk storage tank. An overflow is fitted to the daily use tank and so it is impossible to overfill the daily tank.
  3. The stroke of the dosing metering pump is physically constrained to prevent overdosing. The allowable upper limit is 1 mg/L with a 0.95 mg/L to 1.05 mg/L tolerance.
  4. The dosing pump is wired into the start /stop sequence of the water treatment plant and so will not run on after the plant stops.  
  5. Daily fluoride usage is compared to cross check the dosing rates.

Research

The Australian National Health and Medical Research Council published a systematic review of fluoridation on 14 November 2007. 

More information on Systematic Review of the Efficacy and Safety of Fluoridation (2007) »


The main findings of the NHMRC review may be summarised as follows:

Dental caries

    • There is strong evidence that water fluoridation is beneficial in reducing dental caries.
    • Fluoridation of milk is probably also beneficial in reducing dental caries, although the quality of evidence is weaker than for water fluoridation.
    • The evidence on salt fluoridation is of poor quality and no conclusion can be made on caries prevention.
    • Topical fluoride products are beneficial in reducing dental caries. Combinations may be more effective than single products.

Dental fluorosis

  • There is strong evidence that water fluoridation increases dental fluorosis, however the majority of cases are mild and not considered to be of aesthetic concern.
  • There is some evidence that fluoridated toothpaste increase dental fluorosis. Advice to parents and use of low fluoride toothpaste in young children has reduced the incidence of dental fluorosis.

Fractures


  • The evidence suggests either no effect or a slightly beneficial effect of water fluoridation at optimum levels (0.6 to 1 mg/L) on fractures.
  • The evidence on milk or salt fluoridation, or topical fluoride products is insufficient to make any conclusions on fracture risks.

Cancer

  • There is no clear association between water fluoridation and overall cancer incidence or mortality. Two recent studies showed significant effects on bone cancer, but one study suggested an increase risk while the other suggested a decreased risk.

Other adverse effects

  • A number of studies of lower quality have examined a diverse range of possible adverse effects, however there is insufficient evidence to draw conclusions on any relationship between water fluoridation or other means of fluoride supplementation and adverse health effects.

In a public statement accompanying the review the NHMRC again endorsed its current position that “fluoridation of drinking water remains the most effective and socially equitable means of achieving community-wide exposure to the caries prevention effects of fluoride. It is recommended that water be fluoridated in the target range of 0.6 to 1.1 mg/L, depending on climate, to balance reduction of dental caries and occurrence of dental fluorosis”.