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

To ask His Majesty's Government what is their latest assessment of the amount of microplastics in tap water.

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.

The research by the DWI found that more than 99.99% of microplastic particles were removed through conventional drinking water treatment processes. As a consequence of the removal rates, 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 has also recommended that routine monitoring of microplastics in drinking water was not necessary at this time.