Smartvatten’s fourth Annual Water Report found that “nearly 772 million litres of water were lost to leakages over the course of a year,” across Europe at an estimated cost of at least €3 million. These problems often arise from decades-old infrastructure and machinery and, in ageing pipelines, hidden leaks can persist for days before detection. Here, Mano Koolen, Channel Sales Manager North & East Europe at Ovarro, explains how utilities are shifting from reactive maintenance to proactive monitoring using acoustic technologies like Enigma5 to uncover the unseen and strengthen long-term network resilience.

Ageing infrastructure and rising operational costs place mounting strain on water utilities across Europe. European water utilities are managing pipe networks that, in some cases, are over 100 years old. Climate-related stress, increased demand and stricter regulatory expectations are placing growing pressure on systems originally built for a different era.

Smartvatten’s finding that nearly 772 million litres of water were lost to leaks across monitored European properties is equivalent to more than 300 Olympic swimming pools. And the problem isn’t just volume – many leaks persist undetected for days, driving up non-revenue water and operational costs while undermining sustainability targets.

Faced with budgetary pressures and climate volatility, one solution has been to ‘sweat’ these legacy assets, which means getting the maximum possible value out of assets instead of replacing them. But organisations are discovering that ‘sweating’ legacy assets is no longer a sustainable strategy due to growing demand and extreme weather. The traditional response –  maximise uptime and defer replacement – has reached its limits. Hidden leaks, ageing components and fragmented data make it difficult for utilities to maintain service levels without a smarter, more proactive approach.

Digital insight as a strategic response

Utilities are now turning to digital strategies that prioritise data visibility and early intervention. Rather than waiting for customer complaints or routine inspection cycles to flag issues, operators are exploring real-time monitoring to detect anomalies sooner and act more efficiently.

Smartvatten’s 2025 report highlights the importance of real-time monitoring and data-driven insights in identifying leaks earlier, improving water efficiency and helping organisations respond more quickly to potential issues. The shift is as much cultural as it is technical, moving from reactive maintenance to intelligent oversight supported by actionable data.

For this to succeed, however, utilities need monitoring systems that perform in challenging environments – including buried networks, difficult terrain and legacy infrastructure.

Early warnings for hidden losses

Ovarro’s Enigma5 fixed acoustic logger is designed for continuous leak monitoring in pressurised water networks. Deployed at critical points across the system, Enigma5 devices “listen” overnight — when demand is low — for the distinctive high-frequency signals generated by developing leaks.

In Hamar, Norway, Enigma5 identified a leak releasing 600 cubic metres of water per day. The financial loss was estimated at €2,718 per day, or nearly €1 million per year, and the issue was detected before any visible symptoms emerged. The return on investment was achieved in weeks, not years.

A similar deployment in Oslo saw 75 Enigma5 units reduce night-time water consumption from 80 litres per second to just 22. The municipality reported annual savings of over £100,000, with nearly half directly attributed to early leak detection.

For wider coverage, Enigma5 is often used alongside Ovarro’s portable EnigmaREACH loggers. This hybrid approach allows utilities to combine permanent monitoring with mobile survey capabilities, maximising efficiency without compromising coverage.

Proactive detection, proven outcomes

By enabling continuous oversight of critical assets, Enigma5 allows utilities to reduce unplanned outages, avoid emergency repairs and make smarter use of resources. Maintenance becomes targeted and planned, reducing the need for costly excavation or lengthy investigations.

The data generated also supports broader resilience planning. Integrated with SCADA, GIS and asset management systems, Enigma5 gives utilities a clear view of network performance to help inform investment decisions, demonstrate regulatory compliance and meet environmental targets.

As pressures on the water sector continue to mount, the ability to detect and address issues before they escalate is becoming essential. For many utilities, that shift begins with gaining visibility over parts of the network that have long remained out of sight. Tools like Enigma5 are helping make that possible, supporting a move away from reactive maintenance and towards more informed, proactive management of ageing infrastructure.

To learn more about how Ovarro’s Enigma5 acoustic leak detection systems help utilities uncover hidden losses and improve network resilience, visit the company’s website. www.ovarro.com