Thames Water’s Teddington Direct River Abstraction Pilot Shows PFOS Levels Far Above Legal Limits

Thames Water’s drought-defence scheme, the Teddington Direct River Abstraction (TDRA), proposes to draw up to 75 million litres of water per day from the River Thames at Teddington during low-flow periods and replace it with treated effluent from the Mogden plant via a new tunnel. Pilot tests of the recycling technology revealed rapid increases in perfluorooctane sulfonate (PFOS), a “forever chemical” and suspected carcinogen. Measured concentrations rose to 6.3 ng/L in the first test and 8.7 ng/L in the second, exceeding the UK surface-water limit of 0.65 ng/L by roughly 13-fold. The pilots also recorded elevated iron levels deemed “significantly detrimental” to the river.

The GuardianForever Chemicals Surge 13-Fold in Thames Water Drought Pilots

The Environment Agency, which rejected a similar 2019 proposal on environmental grounds, has received the pilot data and reiterated its legal duty to protect rivers, groundwater and drinking-water catchments from toxic chemicals. An agency spokesperson emphasized that “strict legal requirements” will continue to guide assessments before any development work proceeds. Local opposition includes the Liberal Democrat MP Munira Wilson and the campaign group Solar; its representative Ian McNuff warned that the pilot’s “rapid breakthrough of PFOS” makes reliable operation “unrealistic” under current and future standards.

The Guardian

Thames Water, already burdened by £20 billion of debt, initially priced the TDRA at £350 million. Updated estimates now exceed £500 million, reflecting the need for additional mechanical pumps and carbon-filter upgrades—operations the company describes as “operationally challenging” and costly. The utility also loses about 571 million litres of water daily to leaks, more than seven times the volume the TDRA would supply.

Forever Chemicals Surge 13-Fold in Thames Water Drought Pilots

• “We want to see Pfas banned and the development of a national plan to remove it from the environment, which should be paid for by manufacturers as opposed to water bill payers.” — The spokesperson

The Guardian