Fluoridation of Drinking Water


Fluoridation is the term used to describe the dosing of water supplies to bring the fluoride level up to 1 milligram per litre as a public health measure intended to prevent tooth decay. The maximum permitted value of fluoride in drinking water is 1.5mg/l (milligrams per litre).

In England, the decision to fluoridate your water supply is made by the Secretary of State. When deciding whether to fluoridate the Secretary of State must carry out a consultation exercise, the findings of which must be taken into consideration when reaching a final decision. The law only permits a water company to fluoridate under a contract with the Department of Health and Social Care. The water company has to be consulted about the technical feasibility of any proposed scheme. In Wales, health decisions about fluoridation are taken by the Welsh Government.

The Department of Health and Social Care is responsible for national policy on fluoridation. More information can be found on their website.

The role of DWI in fluoridation

For all water supplies, whether fluoridated or not, the Drinking Water Inspectorate checks that water companies comply with all drinking water regulations. This includes checking that water supplies do not contain more than 1.5mg/l of fluoride. If the standard of 1.5mg/l is breached, then the Drinking Water Inspectorate has the power to take enforcement action to require the water company to rectify the breach. Fluoride occurs naturally in some water sources and enforcement relates to these situations as well as to artificial fluoridation schemes.

When a water company adds fluoride to water supplies, it must do so in a way that complies with the Code of Practice on the Technical Aspects of Fluoridation of Water Supplies 2021. The code can be found on our website. The Drinking Water Inspectorate is responsible for the Code and carries out independent audits of water company dosing facilities for compliance with the Code.

What about the safety of the fluoridation chemicals?

Water companies are only permitted to use specified fluoridation chemicals in accordance with European standards. These standards specify purity levels and producers are not permitted to sell chemicals unless these purity criteria are met.

Is my water fluoridated?

Fluoride is naturally present at low levels in most drinking water in England and Wales. You can obtain a free copy of the water quality test results for the water supply to your home or workplace by contacting your local water company. A map showing typical concentrations of fluoride in drinking water supplies across England and Wales can be found on our website.

The water companies that are currently required by the Secretary of State to fluoridate some or all of their water supplies are:

  • United Utilities
  • Northumbrian Water
  • Anglian Water
  • Severn Trent Water
  • South Staffordshire Water
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