Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, what recent steps he has taken to monitor levels of perfluoroalkyl substances in tap water.

The Drinking Water Inspectorate (DWI) has provided guidance on PFAS to water companies since 2007. In 2021 a guideline value of 0.1 micrograms per litre (µg/L) was adopted for drinking water which, since August 2024 when DWI’s guidance was updated. Companies are required to monitor for 48 individual PFAS in their supplies. These were agreed with the UK Health Security Agency (UKHSA) to be robust levels with an appropriate margin to ensure our drinking water is safe to drink. Concentrations of ‘sum of 48 PFAS’ greater than 0.1 micrograms must be reported to the DWI as a water quality event and all necessary actions to reduce concentrations below this value must be taken. There is no evidence of PFAS concentrations above this value in drinking water supplies.

The DWI continue to monitor publications and advice provided by the World Health Organization and the UK’s Committee on Toxicity in relation to PFAS. It will continue to act accordingly based on the scientific evidence as it emerges, to safeguard public health from the risks from PFAS in drinking water. Work continues across government to assess levels of PFAS to safeguard current high drinking water quality and to ensure our regulations remain fit for purpose.