Thames Water

Built World

Took over operation of the tunnel after the handover reported in August 2026

London's £4.6 billion 'super sewer' cut sewage overflows into the tidal Thames by 86% in its first year, according to the first annual Tideway Benefits Report. The 25-kilometre tunnel is the final piece of a three-phase effort to stop London's combined sewers dumping raw sewage into the river.

Updated Oct 28