Tetra Tech supports South East Water to deliver targeted leakage detection, WaterNet™-driven analytics and active leakage control across Hampshire, Kent, Sussex and Basingstoke, helping to meet ambitious leakage reduction targets and improve network resilience.
Tetra Tech was awarded a framework partnership with South East Water (SEW) in May 2023 to assist in reducing water lost to leakage and improve the overall efficiency of its water networks.
The company has proven expertise in leakage detection and water advisory services from decades of working in various disciplines with a multitude of clients.
South East Water supplies drinking water to 2.3 million people across the South East of England living in parts of Hampshire, Berkshire, Surrey, Sussex, and Kent. Through a network of 9,000 miles of pipe, it delivers 544 million litres of water every day to its customers.
To supply today’s customers, it draws water from more than 250 boreholes, six rivers and six reservoirs. This water is treated at one of its 88 treatment works.
To maintain such a vast and vital service in its current Business Plan, SEW is proposing to invest £1.8 billion in its infrastructure over five years from 2025 to develop new resources, extend and upgrade treatment works and lay new water mains.
Tetra Tech is a critical partner in South East Water’s leakage strategy and provides us with active leakage control resources and specific expertise built up over many years in the industry.
Its field teams are embedded within the operational teams here at South East Water, across all our regions, and not only offer us leakage detection services but support us in many other ways. This includes metering activity, mains network flushing, leakage targeting and reporting (using WaterNet—a spatial asset management and analysis tool), non-household metering, customer-side leakage and pressure logging. Each of these is a strategically important element of South East Water’s leakage reduction programme.
As we approach a new and challenging asset management plan cycle, we look forward to continuing our close and productive partnership, which I am sure will help us meet our targets.
Phil Jones, Head of Leakage Operations at SEW
Challenge
The objective of the partnership between Tetra Tech and SEW is to deliver Leakage Detection and Associated Services to meet SEW leakage reduction targets. This comes after the industry has faced a period of challenging environmental difficulties such as drought and freeze, that have made leakage reduction efforts more challenging. SEW has set the target to reduce the amount of water lost to leakages by 15% for both it’s networks and customer homes between the years 2020-2025.
These ambitions have also been prompted by a performance report from Ofwat that found most UK Water companies had underperformed in their leakage efforts. The UK aims to halve its leakage by 2050, which was highlighted by the National Infrastructure Commission’s ‘Preparing for a Drier Future’ document which depicts why water supply and usage should change to ensure the UK is more resilient to drought.
Another challenge was data and verifying what is in a client’s network, to identify whether it’s allocated water or whether it is in fact a leakage. Organising and managing this information was one of the key goals whilst achieving leakage detection targets. With a dedicated team of experts and specialists behind them, Tetra Tech can deliver services and provide expertise to reach these ambitious targets.
Our role
Contract Management
Our team are responsible for monitoring a large area, split into four sections covering parts of Hampshire, Basingstoke, Kent, and Sussex. Our project optimisation team includes skilled technicians and logging technicians who provide Pressure Flow and Flow Logging services as well as a customer side leakage team. This structured approach ensures we stay aligned, proactive, and efficient when managing the project.
Leakage Detection
Tetra Tech has a detailed and comprehensive suite of high-quality services that allows it to pinpoint leaks. Leakage detection encompasses various methods tailored to swiftly identify and address water loss within distribution networks. Traditional approaches involve meticulous surveying, utilising listening stakes, ground mics, and leak noise correlators to pinpoint potential leakages and more innovative approaches involve step testing and noise logging. This multifaceted approach ensures proactive management of leakage, enabling swift response, and minimising water loss within distribution systems.
Per Capital Consumption
Per Capita Consumption (PCC) deals with areas experiencing persistent issues with water consumption. These areas consistently show high levels of water usage despite efforts to mitigate leakage. Tetra Tech teams, working closely with data analysts and the Data Collection Workforce (DCW) are assigned to investigate and address these issues, involving tasks such as verifying customer counts, inspecting boundary valves, and identifying potential breaches or anomalies.
Utilising technology
Prior to the introduction of WaterNet, data analysis and insight was a predominantly manual process. WaterNet is a spatial asset management reporting and analysis tool which efficiently collates data from selected sources and converts it into integrated asset management information. It allows our clients to precisely identify where and how they need to focus their efforts through effective data integration and analysis.
WaterNet is a spatial asset management reporting and analysis tool which efficiently collates corporate data from selected sources and converts it into integrated asset management information.
The impact
Tetra Tech has the capabilities and expertise to support and deliver SEW’s leakage reduction ambitions over the rest of AMP7 and into AMP8 for the ongoing periods of this strategic partnership.
At a glance
Client
South East Water
Location
South East England, Hampshire, Basingstoke, Kent, and Sussex
Services
Active leakage control, associated services, WaterNet
The project featured in this article was undertaken by RPS, A Tetra Tech Company and originally published on RPSgroup.com. In March 2026 RPS rebranded to Tetra Tech.