Frequently Asked Questions

Fluoridation of Drinking Water

Introduction

Fluoridation is the term used to describe the addition of a fluoride chemical to water supplies to raise the fluoride level to 1 milligram per litre (1mg/l = 1 part per million), to prevent tooth decay. 

The maximum fluoride concentration permitted in drinking water under the Water Supply (Water Quality) Regulations 2000^[1] is 1.5 mg/l.

The legal position

Under the Water Industry Act 1991 the law previously allowed water companies to carry out fluoridation when requested to do so by Health Authorities, but they were not obliged to agree to a request. This was changed by the introduction of the Water Act 2003. Section 58 of the Water Act 2003 amended the legislation so that water companies now have to fluoridate drinking water supplies if asked to do so by a Strategic Health Authority (SHA). Before any new fluoridation scheme can be put in place the SHA must complete a local consultation process and provide the water company with an indemnity against costs . Note: For water supplies in Wales the decision on whether or not to fluoridate would be taken by the Welsh Assembly Government.

The Department of Health is responsible for national policy on fluoridation, more information can be found on their website www.dh.gov.uk.

The role of DWI in fluoridation

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.  In the unlikely event that the standard of 1.5mg/l is breached, DWI can take enforcement action against the water company to require it to rectify the breach.  For serious breaches of the standard, DWI would consider prosecution of the water company for supplying unfit water.  All these measures are to protect public health.

What about the chemicals used?

The addition of any chemical or compound to drinking water in England & Wales is very strictly regulated.  Water companies are only permitted to use fluoridation chemicals that comply with strict European standards.  These standards incorporate strict purity criteria and there is a binding obligation on the producers to supply chemicals that conform with the criteria specified. 

Is my water fluoridated?

Fluoride is naturally present in some drinking water due to the water being drawn from the ground where the rock strata have higher natural fluoride concentrations. 

In some other areas fluoride is added to water supplies at a dose adjusted to give a final concentration of 1 mg/l.  When a water company adds fluoride to water supplies, it must comply with the Code of Practice on the Technical Aspects of Fluoridation of Water Supplies. The Code of Practice contains guidance on the design, installation, operation and maintenance of fluoridation equipment. 

A map showing the average concentration of fluoride in drinking water supplies (pdf format 1103KB) is available.

Your water company can provide further information on the concentration of fluoride in your drinking water and confirm whether or not fluoridation is practised in your local area.