As extreme weather events become more frequent and the government mandate to build new homes becomes more prevalent, pressures on the UK’s drainage infrastructure continue to mount. Early indications of AMP8 show a key focus on reducing Combined Sewer Overflow (CSO) spills to a level deemed “acceptable” by DEFRA.
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Josh Wilce – Regional Director, Water & Environment at Waterman Aspen
Among the lesser-seen and often deemed “too hard to address” challenges is infiltration - the ingress of groundwater into the sewer network. Hidden underground, it is a silent disruptor contributing to capacity issues within treatment and pumping stations, leading to raw sewage entering our rivers and waterways. It can account for up to 40% of domestic flow in some networks, increasing the burden on already strained treatment facilities.
We’re introducing an AI-powered infiltration detection tool to the UK in collaboration with Waterman’s parent company, CTI Engineering in Japan. Originally developed to monitor Japan’s earthquake-prone sewer networks, this technology is poised to revolutionise how we detect and manage infiltration across the UK’s ageing infrastructure.
Traditional detection uses flow loggers installed at the base of manholes which is time-consuming, costly, and risky. CTI Engineering’s approach assesses flow using acoustic sensing and AI analysis. A suspended logger records the sound of the flow from the top of a manhole; the data is analysed across 200+ inputs to detect anomalies caused by infiltration.
The AI builds baseline flow patterns for dry and wet weather, then flags sections where water may be infiltrating through cracks or faults. This avoids human entry for data collection, allows more loggers to be installed per day, reduces road closures and traffic management, and cuts costs by more than half compared to traditional methods. The AI greatly reduces analysis time and helps eliminate human error in interpreting flow logs.
In Japan, the system has been deployed at 200+ sites. A Kobe case study across 85 hectares with 32 sensors showed how quickly and accurately infiltration points can be pinpointed.
In the UK, Waterman Aspen and CTI are seeking trial sites with Water Companies. Early interest has come through the SPRING innovation process, and discussions are underway to initiate UK-based trials. To meet UK safety requirements, the team has secured ATEX certification, ensuring compliance for explosive atmospheres typical of sewer environments. The goal is a side-by-side comparison of AI analysis versus traditional loggers on a known infiltration network.
Infiltration affects highways drainage, wastewater systems, and Lead Local Flood Authorities (LLFAs) alike. Combined sewers remain common across the UK, so infiltration from highways and surface water systems directly impacts downstream sewage capacity, with environmental and societal costs.
A smarter detection method can aid LLFAs and highways authorities in their statutory duties and support strategic drainage planning, offering a collaborative pathway to meet AMP8 objectives while minimising disruption to the transport network.
By improving detection accuracy, this AI-powered system focuses resources on known problem areas - avoiding unnecessary maintenance, repair and renewal. Targeted works mean less road disruption, fewer emergency CSO spills, and better protection of watercourses during heavy rainfall events.
There is a carbon angle too: reducing unnecessary inspections and treatment plant loads contributes to net-zero goals. Better data means better decision-making - something regulators and water companies increasingly demand.
A growing skills shortage - with engineers moving to sectors like energy - has left gaps in data analysis and system design. AI tools like this can amplify capacity, enabling fewer specialists to do more. There is also an opportunity to bring in people with AI or data expertise from outside the sector.
The industry has traditionally stuck to what it knows best, but to meet the demands of AMP8 and beyond, we must welcome new thinking, new tools, and new talent. Waterman Aspen’s approach - bridging innovation from CTI Japan with UK water challenges - shows how multinational collaboration can align to solve entrenched problems.
Free trials are being offered to validate the technology in UK conditions; an opportunity not just to test new methods, but to shape the future of infrastructure management. If you are a drainage authority, water company, or infrastructure partner interested in trialling this tool, please contact Josh Wilce via Waterman Aspen for more information.
Waterman Aspen welcomes engineers and technical specialists to make their mark on some of the biggest infrastructure projects across the UK on a secondment basis. We have built careers and provided technical expertise to our clients for over 30 years. Put simply, we provide the right people, with the right skills for the job, at the right time – for as long as our clients need them.
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