Poly and Perfluorinated Alkyl Substances (PFAS)

The Inspectorate provides general guidance on PFAS.

In March 2025, a consolidated guidance document was issued to water companies detailing the Inspectorate’s requirements regarding PFAS monitoring, risk assessment, and strategy in relation to public water supply systems.

Research and data gathering on PFAS in water sources and drinking water supplies is ongoing. As we learn more our guidance will become more informed.

The World Health Organization (WHO) has produced a guidance document on PFOS and PFOA in drinking water.

Private water supply risk assessment

Due to the wide range of PFAS sources entering the environment, and the persistence of the substances, it is recommended that the potential for the presence of PFAS is included when conducting risk assessments of private water supply systems. This should inform the monitoring plan.

Risk based monitoring advice on PFAS in private water supplies can also be found on our website.

Analysis

Laboratory capability and capacity is expanding, with analytical methods being developed to enable detections of a larger range of PFAS, at ever finer concentrations.

The United Kingdom Accreditation Service (UKAS) is the organisation responsible for accrediting the analytical capabilities of laboratories.

The UKAS website lists laboratories currently accredited for PFAS analysis.