Developing a market-based approach to deliver SuDS through street works

Competition: Breakthrough 4: Catalyst

Amount awarded: £1,340,610

Led by: Thames Water

Partners: Greater London Authority

Estimated completion date: April 2026

Water cycle tag: Waste water network

The risk of flooding in London from heavy rain is increasing. This project incentivises utility companies to refill some of the 165,000 holes they dig in London every year with ‘sustainable drainage systems’ (such as raingardens). These will reduce strain on drains from rainwater and create a greener city. 

“We already work with the GLA and other utility companies to deliver shared streetworks projects to reduce disruption to Londoners. This project will take it to the next level, using the opportunities created by street works to deliver green flood risk solutions that will benefit customers, society and the environment.” – Nevil Muncaster, Engineering & Asset Director, Thames Water 

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Update from the project (July 2025)

The project has achieved several key milestones to support the development of a scalable and effective SuDS (Sustainable Drainage Systems) market. We’ve completed a technical review of existing modelling tools and created a framework to assess their real-world suitability, helping shape how future SuDS investments are valued and delivered. A global review of SuDS design standards has been completed, and draft specifications for five typical system types have been reviewed with Thames Water to support consistent, large-scale delivery via standard streetworks processes. We’ve developed a data platform identifying eligible areas for SuDS delivery and defined bidding approaches across geographic scales. A market simulation in Enfield showed SuDS delivery through the market could achieve cost savings of 19% – 26%. Five sites have been identified to progress three pilot schemes. Contractors and suppliers have been engaged, with plans and designs underway to ensure delivery by April 2026. The tradable unit has been confirmed as Reduction in Surface Water Volume (RSWV), and an accreditation standard has been developed to validate how SuDS projects generate RSWV credits. Statutory constraints have been mapped and mitigation strategies are in development. Planning is ongoing for broader industry engagement and the next phase of development.