Costain awarded £150m Thames Water wastewater upgrade contract

Costain has been awarded a £150 million contract by Thames Water to perform wastewater treatment upgrades at 15 sites across the Thames Valley. The project is part of the Wastewater Asset Assurance Programme, which falls under Asset Management Plan 8 (AMP8) scheduled from 2025 to 2030.

Thames Water describes this investment as its largest modernization of sewers and sewage treatment works in over 150 years. The broader programme aims to improve infrastructure at more than 250 sites. The specific work for Costain includes upgrading inlet stations, improving storm tank resilience, and performing various repairs and modifications to wastewater treatment systems.

The project will be managed in two geographical regions. Eastern sites include Barkway, Brentwood, Long Reach, Little Hallingbury, North Weald, and Standon. Western sites include Aldershot, Burghfield, Esher, Horley, Lightwater, Marlborough, Northleach, Waddesdon, and Windsor.