Thames Water's Β£840 Million Infrastructure Push - Critical AMP8 Projects
Executive Summary: Thames Water's Strategic Infrastructure Investment
Thames Water has taken a significant step toward delivering Β£840 million worth of major capital projects aimed at enhancing its wastewater and water treatment sites, following the publication of its Procurement Specific Questionnaire (PSQ) for suppliers on September 23, 2025. This represents a crucial component of the company's record Β£20 billion infrastructure investment programme over the next five years.
[cite author="Tim Horton, Major Projects and Programmes Director" source="Thames Water announcement, Sept 23 2025"]Our purpose is to deliver life's essential service, so our customers, communities and the environment can thrive. We're embarking on a record Β£20 billion investment over the next five years to transform our infrastructure, enhance environmental performance, and deliver better services for our customers.[/cite]
The scale of this investment is unprecedented in Thames Water's history and comes at a critical time when the UK water sector faces mounting pressure to modernize aging infrastructure while meeting stricter environmental standards.
Project Scope and Strategic Locations
The 10 major capital projects strategically span seven wastewater treatment sites and two water treatment sites, designed to improve infrastructure resilience, environmental performance, and support population growth across London and the Thames Valley:
Wastewater Treatment Sites:
- Riverside Sewage Treatment Works
- Beckton Sludge Powered Generators replacement
- Beckton Sewage Treatment Works Water Asset Assurance Programme
- Crossness Sewage Treatment Works
- Didcot Sewage Treatment Works
- Wantage Sewage Treatment Works
- Bicester Sewage Treatment Works
- Hogsmill Sewage Treatment Works
Water Treatment Sites:
- Ashford Water Treatment Works (Ultraviolet Treatment)
- Hampton Water Treatment Works (Ultraviolet Treatment)
The inclusion of UV treatment at both water treatment sites indicates Thames Water's commitment to enhanced pathogen removal and water quality improvements, addressing both current regulatory requirements and future-proofing against emerging contaminants.
[cite author="Tim Horton" source="Thames Water, Sept 23 2025"]Building long-term, collaborative relationships with experienced delivery partners, so we can deliver at pace, is critical to the success of our AMP 8 programme.[/cite]
Procurement Timeline and Industry Engagement
Thames Water welcomed prospective bidders to its Reading offices on September 18, 2025, as part of the formal launch of its procurement process. The event provided an overview of what to expect as part of the procurement process as well as a review of the outcomes of the company's preliminary market engagement phase.
[cite author="Water Magazine" source="Sept 23 2025"]The water company said the event provided an overview of what to expect as part of the procurement process as well as a review of the outcomes of the company's preliminary market engagement phase.[/cite]
The procurement timeline indicates:
- September 2025: PSQ publication and supplier engagement
- November 2025: Formal bidding process begins
- March 2026: Target for signed framework agreements
- AMP8-AMP9: Additional projects added to framework (2025-2035)
Broader Context: AMP8 Investment Landscape
This Β£840 million programme forms part of Thames Water's response to Ofwat's final determination, which set the company a total expenditure allowance of Β£20.5 billion for the 2025-30 period - Β£4.0 billion lower than Thames Water requested. Despite this reduction, the investment represents the largest infrastructure programme in the company's history.
[cite author="Tim Horton" source="Thames Water, Sept 23 2025"]The launch of our Procurement Specific Questionnaire and recent supplier engagement event mark important milestones in our journey to strengthen our procurement process and ensure we're ready for the formal bidding phase in November.[/cite]
Financial Challenges and Regulatory Pressure
The announcement comes amid significant financial challenges for Thames Water. The company has deferred its Competition and Markets Authority reference until October 22, 2025, and faces a Β£24.5 million penalty payment due by September 30, 2025, related to wastewater business violations (Β£104.5m) and dividend payment issues (Β£18.2m).
Despite these challenges, the infrastructure investment is proceeding, driven by regulatory requirements and the urgent need to address:
- Aging infrastructure requiring immediate attention
- Population growth in London and Thames Valley
- Stricter environmental standards
- Climate resilience requirements
Supply Chain Implications
The PSQ process represents a significant opportunity for the UK construction and engineering sector. Thames Water is seeking partners who can demonstrate:
- Technical capability for complex water infrastructure projects
- Financial stability for long-term partnerships
- Experience with similar scale projects
- Commitment to environmental and safety standards
- Ability to deliver at pace within AMP8 timescales
The framework approach allows flexibility to add projects throughout AMP8 (2025-2030) and AMP9 (2030-2035), providing long-term visibility for successful contractors.
Future Outlook
The Β£840 million investment represents just 4.2% of Thames Water's total Β£20 billion AMP8 programme, indicating significant additional procurement opportunities ahead. The focus on collaborative, long-term partnerships suggests a shift from traditional transactional procurement to more integrated delivery models.

