River Thames pollution levels found to be at harmful levels by environmental action groups

Surfers Against Sewage are among the environmental campaigners that have tested 24 sites to the west of London, since March 2024. A total of 210 tests have been carried out with 47 of these indicating excessive levels of e-coli and intestinal enterococci.

Water pollution caused by illegal discharges into river has been widely reported in the UK over recent years – there have also been instances when the sewage system is overstretched, due to heavy rainfall. Thames Water has stated that the company is "committed to seeing our waterways thrive" and is making improvements at 250 sites to help minimise overflow discharges.

Official reports have shown that the amount of time in which sewage was dumped into the Thames have more than quadrupled in the last year. Plans by Thames Water to take more water from the river at Teddington, voted as the ‘best place to live in London in 2023 by the Sunday Times, and replace that water with recycled sewage effluent from the nearby Mogden treatment works, based in Isleworth, has attracted significant opposition.

A Thames Water spokesperson stated, "While all storm discharges are unacceptable, the sewage system was historically designed to work in this way, to prevent sewage backing up into people’s homes."

200 site upgrades are under way including a £100m upgrade of the Mogden sewage treatment works, which the spokesperson claimed would increase treatment capacity and reduce storm discharges.