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

To ask the Secretary of State for Environment, Food and Rural Affairs, what recent assessment his Department has made of the prevalence of microplastics in UK drinking water sources; and what steps he has taken to regulate and reduce microplastic pollution in the water supply chain.

Drinking water quality is a devolved matter and therefore I can only respond in relation to England.

The Drinking Water Inspectorate (DWI) has published two research projects on microplastics in drinking water – one in January 2019 reviewing the potential risks from nanoparticles and microplastics and another in October 2022 looking at the removal of microplastics by drinking water treatment processes. This found that more than 99.99% of microplastic particles were removed through conventional drinking water treatment processes and that microplastics were present at very low levels in drinking water. Their contribution to total daily exposure, and presenting a potential risk to human health, was likely to be low or insignificant. The World Health Organization (WHO) has also recommended that routine monitoring of microplastics in drinking water was not necessary at this time.

The DWI published a report in December 2024 recommending revisions to some of the parameters listed in the drinking water regulations.