About 90% of Australians drink public water with fluoride added to it. Most never chose that, and many don't know it happens. This guide explains why it's done, who decides, and what the debate is actually about.
The short answer
Fluoride is added to reduce tooth decay. Fluoride at low levels helps tooth enamel resist acid and repair early damage. Health authorities decided in the 1950s and 60s that adding it to the water supply was the cheapest way to reach everyone, including people who don't brush or see a dentist.
How much is added
Utilities dose to between 0.6 and 1.1 milligrams per litre. Hotter places sit at the low end because people drink more water. NSW, for example, targets 1.0 mg/L with an operating range of 0.9 to 1.5 mg/L. The health-based maximum in the Australian Drinking Water Guidelines is 1.5 mg/L.
Most large plants add hydrofluorosilicic acid, a co-product of phosphate fertiliser manufacturing.
What the official evidence says
The NHMRC's 2017 review found fluoridation reduces tooth decay by 26 to 44% in children and adolescents and by about 27% in adults. It found no reliable link to cancer, Down syndrome, hip fracture or lower IQ at Australian levels. A 2026 Queensland study of 7,748 schoolchildren found decay fell mainly in fluoridated areas.
What critics argue
- Consent. Water fluoridation treats everyone, regardless of age, health or wishes. Opponents say a medical-style intervention should be a personal choice.
- Dose can't be controlled. A labourer drinking four litres a day gets several times the fluoride of an office worker. Infants on formula made with tap water get more per kilogram than adults.
- New research. A 2024 US National Toxicology Program review linked exposures above 1.5 mg/L with lower child IQ. Supporters point out this is above Australian levels. Critics point out the margin isn't large.
- Toothpaste exists. Topical fluoride from toothpaste is widely available, which critics argue makes water fluoridation less necessary than in the 1960s.
- Systems fail. Dubbo went eight years without it, and a Brisbane suburb was overdosed in 2009.
Where it isn't added
Every capital city fluoridates. The exceptions are mostly regional. Queensland is the outlier: only 16 of its 77 councils still add fluoride, after the state handed the decision to councils in 2012. Cairns, Mackay, Rockhampton, Bundaberg and Gladstone don't add it. In NSW, Byron Shire is the best-known holdout. Some towns, like Julia Creek and Quilpie in Queensland, have natural fluoride above the guideline level.
Is it changing?
The NHMRC is reviewing its fluoride advice in 2026. Abroad, Utah and Florida banned fluoridation in 2025, while New Zealand's courts upheld central-government orders to fluoridate. Australia's position hasn't changed yet, but the evidence is being looked at again for the first time in nearly a decade.