South West Water partnered with Grundfos to transform high-volume telemetry into actionable intelligence – reducing false overflow alerts, enabling proactive blockage detection and improving operational efficiency across a complex sewer network.
South West Water
A UK water and wastewater company, South West Water provides services to 1.8 million customers across Cornwall, Devon, the Isles of Scilly, and parts of Dorset and Somerset.
Remote telemetry specialist Grundfos has partnered with South West Water to implement an advanced analytics solution for combined sewer overflow monitoring and proactive blockage detection.
South West Water (SWW) has drastically reduced false alarms and increased operational efficiency since deploying Grundfos’s advanced analytics platform across its region in 2023.
The platform directly supports SWW’s commitment to reducing pollution and improving environmental performance, which has seen pollution incidents halve in the eight months to August 2025, with storm overflow spills reducing by nearly 50% between 2024 and 2025. The utility also cleared over 7,000 avoidable blockages from its networks, underscoring the vital need for targeted intervention.
The situation
Data challenge
SWW maintains and operates 14,332 miles of sewer and has, a year ahead of the government’s target, fitted 100% of its 1,342 storm overflows with Event Duration Monitors (EDMs).
While this multi-million-pound investment delivers streams of data – with some sites capturing updates as often as every 10 seconds – the critical challenge is interpreting this information to isolate genuine issues.
The core problem was that the water company’s telemetry system could generate up to 10,000 alerts a month for highlevel events. If the control room flagged all 10,000 alerts, they would all have to be investigated – but 9,500 are rainfalldominated and therefore counted as ‘not genuine’. This creates an immense workload and leads to alarm fatigue.
This challenge is not unique to SWW, and the high rate of false positives across the water sector has significant negative impacts including wasted resources, operational inefficiency and reduced confidence in monitoring systems. Every false alert diverts the attention of operators and field teams away from issues, leading to time and effort spent investigating non-existent problems. In addition, false positives can trigger unnecessary actions, such as system shutdowns, additional costly laboratory analyses, system re-cleans, and unnecessary chemical treatments.
Working with Grundfos has transformed how our control room manages the overwhelming volume of overflow alerts.
The solution
Intelligence over volume
To support SWW in reducing non-genuine alerts, Grundfos implemented a multi-faceted solution, using its proprietary Grundfos Connect Sewer Analytics+ platform – a compact, self-contained software solution designed for high-frequency data and real-time responsiveness.
Its most recent update is designed as a much smaller piece of software – providing cross-platform support and dramatically improved performance. In addition, the update enables the processing of much higher frequency data – ranging from typical 15-minute SCADA feeds, down to one-minute data, one-second data, and even, in the future, sub-second/millisecond data for sensitive applications like pressure trend analysis.
The platform architecture is also designed to support edge computing – where data is processed locally – to enable faster responses and reduce the need to send large amounts of raw data over a network.
The outcome
Alert reduction
Grundfos monitors approximately 1,500 combined sewer overflow (CSO) sites for SWW, including standalone outfalls, pumping stations and storm tank overflows. By performing sophisticated dry and wet weather analysis using integrated level and rainfall data, the telemetry stream is filtered, focusing only on events that are not caused by rain.
The resulting efficiency is substantial. The system identifies that out of the 10,000 alerts generated by the telemetry system, only around 500 may be relevant, thereby eliminating the need to look at 9,500 non-genuine (false) alarms during rainfall-dominated events. This results in an alert accuracy of around 95 percent.
The solution integrates several datasets and intelligent features to prevent non-critical alarms. Underground saturation data is incorporated to help accurately model extended spill periods, while inhibiting alerts are activated on coastal CSOs during high tides to prevent false alarms from leaking tidal flaps.
In addition, integration with Grundfos’s global artificial intelligence (AI) team means predictions of sewer levels on storm tanks can be provided up to 12 hours in advance, meaning companies can inhibit alerts on long-duration spills that can last for weeks.
The intelligent Grundfos system allows our teams to focus their efforts where they are needed most – preventing genuine blockages and protecting the environment.
Proactive detection
The Grundfos Connect Rain & Sewer Analytics service focuses on identifying partial blockages and dry weather spills that are key precursors to major incidents.
This proactive approach is already demonstrating significant results: since 2023, SWW has identified around 240 confirmed blockages and other obstructions, which prevented incidents evolving. Technicians were able to attend in a timely manner and fix issues efficiently. Due to the high alert accuracy, the number of false positives has reduced to just four per cent.
Beyond preventing spills, the service has proven invaluable to SWW’s teams for many other purposes including data validation, identifying faulty sensors, installation issues and inaccurate level values. These insights have led SWW to undertake significant remedial work, including site visits to remeasure spill heights on all CSOs.
Flow estimation
By simplifying the flow monitoring hardware and removing the pressure sensor component, a near-tenfold cost reduction on capturing flow volumes was achieved. This simplification drastically cuts installation time as the sensors are attached to the outside of the pipe, eliminating the need to cut down, halt the flow, or drain the system. This dramatically reduces downtime, labour, and the risk of contamination. Using this approach, the process of installing monitors was reduced from a day-and-a-half to approximately one hour.
For SWW, this intervention means reduced operational expenditure from treating lower volumes of water, reduced implementation costs, and better data for remediation. In addition, the measures have improved outcomes for SWW’s sustainability ambitions and for the environment, decreasing energy consumption and reducing the risk of pollution incidents from sewer overflows.
Most importantly, SWW customers benefit from a lower risk of sewer flooding and long-term cost savings due to the utility’s increased efficiency.
Infiltration innovation
In a supplementary project, Grundfos AI expertise delivered a data-driven approach to flow estimation in SWW pumping stations, helping quantify infiltration – groundwater entering sewer networks through defects like pipe cracks, broken joints, or root intrusion – cost-effectively. The data is processed in the Grundfos AI cloud and displayed via the analytics platform for actionable insights.
In the UK, water and sewerage companies are legally responsible for managing infiltration under the Water Industry Act 1991 and environmental permitting regulations governed by the Environment Agency.
They are expected to:
Grundfos supplied:
- Grundfos Connect Rain & Sewer Analytics platform
Facts:
- Topic: Sewer level monitoring and analytics
- Location: South West England, United Kingdom
- Customer: South West Water
Ongoing collaboration
The two-way collaboration between SWW and Grundfos is maintained through monthly meetings where site challenges are reviewed to ensure continuous service improvement. The new Grundfos analytics dashboard is alert-centric and designed to support management-by-exception, refreshing asset and alert capture approximately every minute. The update is geared toward addressing critical sector challenges around sewer network management, reflecting the needs of the latest Asset Management Plan (AMP) period - 2025-2030.
The success of the partnership is best summarised by Nathan Green, process development analyst at SWW:
“Working with Grundfos has transformed how our control room manages the overwhelming volume of overflow alerts. Their intelligent system now enables us to cut through the noise, significantly reducing the non-genuine, rainfalldominated alarms, and allowing our teams to focus their efforts where they are needed most – preventing genuine blockages and protecting the environment. The result is a more efficient, proactive approach to network management.”
Key benefits
This project was originally implemented by Metasphere, a company acquired by Grundfos in 2023. The full Metasphere range of remote monitoring products and solutions for water and wastewater networks and environmental applications is now available through Grundfos.
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