Tideway has announced the successful activation of the new super sewer, ushering in a healthier future for London’s iconic river. 

After ten years of construction, the last 21 connections have been made between the original Victorian sewers and the new 25 km Thames Tideway Tunnel, bringing the entire system online to protect the tidal Thames from sewage pollution. Connections have been made at landmark locations including the starting point of the University Boat Race at Putney Embankment; Chelsea and Victoria Embankments; Blackfriars Bridge in the heart of the City of London; and King Edward Memorial Park in Wapping. The 25 km-long super sewer connects to the 6.9 km-long existing Lee Tunnel, a Thames Water asset – forming the ‘London Tideway Tunnel’ (LTT) system. Construction on the project started in 2016, spanning 24 sites from Acton in west London to Abbey Mills Pumping Station in Stratford, east London. 

Over 20 deep shafts, some as wide as St Paul’s Cathedral’s dome, were built across London to redirect sewage and lower tunneling machines underground. The first machine began operation in 2018, completing primary tunneling for the 25km main tunnel and two smaller connection tunnels by 2022. By autumn 2023, secondary tunnel lining was finished, with major civil engineering work concluding in spring 2024.

The Tideway project is being delivered by an alliance of contractors. The west region is being delivered by a joint venture of BAM Nuttall, Morgan Sindall Infrastructure and Balfour Beatty. The central region is being delivered by a joint venture of Ferrovial Agroman UK and Laing O'Rourke. The east region is being delivered by a joint venture of Costain, Vinci Construction Grands Projets and Bachy Soletanche.  System integration is being delivered by Amey, which is responsible for providing process control, communication equipment and software systems for operation, maintenance and reporting across the Thames Tideway Tunnel system.  The project is on track to be fully complete (with testing complete) later in 2025. Thames Water will then operate the system, as part of its London wastewater network.