Trunk Main Losses

Trunk mains are among the most critical assets operated by the water industry. A catastrophic failure of a trunk main is hugely destructive and can leave thousands of customers without water, communities with damage to properties, restricted transport links, the local economy adversely affected and the environment damaged.

WLLS are Critical Infrastructure Leakage Detection specialists, and trunk mains are at the core of our business.

Our dedicated trunk main teams are experienced in performing trunk main leakage surveys and have a track record of getting results where others fail to.

They carry state-of-the-art leak location equipment and can additionally call on specialist skills and techniques where necessary in order to get the result.

Trunk mains do not tend to burst as frequently as distribution mains, and so probabilistic methods of estimating deterioration are not appropriate.
Instead, the industry tends to use historic leakage as a proxy for pipe condition. The problem with this approach is that trunk main leakage is technically extremely challenging to detect, initially in terms of awareness times due to measurement uncertainties, but also (and critically) in terms of location.

The many challenges faced by the industry include:

  • High noise environments, often operating at higher velocities and in the vicinity of pumps, PRVs and other control valves
  • Difficulties in monitoring and localising due to measurement uncertainty in the mass balance
  • Availability, location, accessibility and serviceability of valves, washouts and hydrants along the trunk main
  • The physical length between fittings, which can test the limits of acoustic correlation techniques
  • The operational difficulties involved with step testing or any invasive methods
  • Low operating pressures in the vicinity of services reservoirs

These factors, often exacerbated by local issues, make trunk main leakage detection challenging and often carried out by walking the main and top sounding.

Why trust your most critical infrastructure to generalists? Contact us and let the specialists show you what we can do.


Water Leak Location Services was established in 2013 to assist UK and International Water Utilities in tackling trunk main leakage and locating leaks in difficult site conditions.
Registered office: Unit 2 Basepoint Business Centre, Waterberry Drive, Waterlooville, Hampshire, PO7 7TH
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