8 Sep 2026
London begins SuDS through Streetworks Market programme
SuDS through Streetworks: London Begins New Programme
London is beginning work on a new mechanism for delivering SuDS through streetworks, using planned utility and highway works as opportunities to install sustainable drainage systems. The initiative could make climate resilience projects less costly and disruptive, although its benefits still need to be demonstrated through live market pilots.
The Greater London Authority approved funding arrangements for the SuDS through Streetworks Market on 5 August 2026. Mobilisation starts in September, with the programme intended to run until April 2031.
Turning routine excavations into resilience projects
When a utility company or highway authority excavates a street, the normal response is to reinstate the original hard surface. Under the proposed market, organisations seeking flood resilience improvements, such as boroughs, could fund the installation of rain gardens or other sustainable drainage systems as part of that reinstatement. This would allow the drainage work to share excavation, traffic management and mobilisation costs with an existing streetworks programme.
The GLA’s Infrastructure Coordination Service and Thames Water developed the model. The 16 partners completed an earlier £1.34 million development phase in May 2026. It examined how planned works could be matched with locations where sustainable drainage would provide the greatest value. Thames Water’s project summary confirms that this preparatory phase has now concluded.
A £6,869,054 award from the Ofwat Water Innovation Fund supports the next stage. Ofwat describes the project as a way to connect organisations requiring flood resilience with utility companies already carrying out excavations. In the longer term, the project aims to create a framework that could be applied elsewhere in the UK. Ofwat announced the award in May.
Under the August mayoral decision, the GLA can receive and spend up to £4,190,376 of the funding through its partnership with Thames Water. This allocation will principally support programme management, staffing, technical expertise and market development. It will not directly fund construction across London.
What the programme will test
The initial work will focus on the Lee Valley and Central London surface water catchments. The programme will establish governance arrangements, data systems and contractual partnerships before running two complete rounds of bidding and matching. In practice, this means testing whether prospective buyers of flood resilience measures can identify suitable locations and agree delivery with utilities or highway authorities that already have works planned nearby. Analysis from the previous development phase suggested that the approach could:
- produce cost efficiencies of approximately 27%
- identify as many as 68,000 potential SuDS delivery opportunities for lead local flood authorities
- save more than 20 days of road and community disruption, on average, for each project delivered
These figures are projections from the development work, not measured results from a mature operating market. The live pilots will therefore be important in establishing which opportunities are technically viable, commercially attractive and capable of securing the necessary approvals. The GLA’s full mayoral decision sets out a formal project launch in February or March 2027. Staged development and evaluation will then continue through to 2031.
Why SuDS through streetworks matters for the built environment
The programme is testing whether delivering SuDS through streetworks can address a familiar infrastructure problem. Different organisations often plan and fund work in the same public realm without aligning their programmes early enough to share costs or reduce disruption.
The market could give developers, designers and local authorities another route for delivering drainage and public realm improvements beyond the boundary of an individual site. This may be particularly relevant where development depends on wider catchment resilience, constrained drainage networks or improvements to streets adjoining several projects. It could also encourage teams to consider utility programmes as part of early site and infrastructure strategy. A planned water, energy or communications excavation may become a delivery opportunity if it coincides with a priority location for surface water management.
Thames Water reports that approximately 186,000 streetworks take place in London each year, creating a substantial number of potential opportunities to integrate sustainable drainage into planned works. Its funding announcement says the programme is intended to test how even a proportion of these works could support greener infrastructure.
Practical points for decision makers
Project and asset teams should watch four areas as the pilots develop.
First, coordination will need to start well before a contractor arrives on site. Teams will need to align drainage priorities, utility programmes, highway consents and funding decisions early enough to influence design and procurement.
Responsibility for completed assets will be crucial. The programme will need workable arrangements for adoption, inspection, maintenance and long term performance, particularly where several organisations contribute to delivery.
Not every excavation will suit a sustainable drainage intervention. Underground services, highway geometry, contaminated ground, accessibility, road safety and maintenance access could all restrict what is feasible.
Finally, the programme does not itself change planning policy, building regulations or statutory drainage duties. Nor does the funding create an automatic source of capital for individual developments. Its immediate significance lies in testing a new method of coordinating and purchasing infrastructure.
A practical test of collaborative delivery
The SuDS through Streetworks Market goes beyond a conventional demonstration project by attempting to establish repeatable commercial and governance arrangements. Its value will depend on whether the pilots convert mapped opportunities into maintainable assets at a lower whole life cost.
The programme also highlights the potential value of planning drainage, utilities, highways and development programmes together to deliver climate resilience more efficiently.
