Across 3,169 District Metered Areas (DMAs) and six regions of the UK, only one pipe material showed a clear, statistically significant link to higher leakage: cast iron, and only in towns and cities. That single finding could reshape where the sector spends its replacement budget.
It is one of several insights from our latest project for UKWIR, Understanding factors contributing and affecting DMA leakage, delivered with Dayworth Consulting. The work tackles a stubborn problem: why do similar leakage tactics give such different results from one DMA to the next, and how can we close the skills gap as experienced leakage engineers retire faster than they can be replaced?
What we did
We worked in three phases. First, a survey and twelve interviews with leakage practitioners gave us the variables that matter on the ground. Second, we built one of the largest DMA datasets ever assembled for this kind of study — 3,169 areas across five companies — and modelled the relationships using Bayesian Networks. Third, we turned those relationships into thirteen practical “scenarios” and a playbook tool that any company can use to classify its own DMAs and plan a tailored Active Leakage Control response.
What we found
Rural DMAs leak more, even after we strip out the effects of network size and customer density. Pressure, pipe age and connection density all play a measurable role. And cast iron in urban areas stands out as the one material with a clear leakage signal; this is important, because urban replacement is often pushed down the priority list on cost grounds. The Combined Real Losses Index (CRLI), used internationally at company level, also proved its worth at DMA scale, giving the sector a fairer way to compare areas with very different shapes and sizes.
Why it matters
Leakage targets are tightening, the workforce is changing, and the cost of getting it wrong is rising. The playbook tool puts a structured, evidence-based response in the hands of every engineer, not just the most experienced ones, and gives strategy teams a clear view of where their network sits against the wider industry. It is a practical step toward the sector’s shared goal of zero leakage by 2050.
What comes next
The playbooks are ready to use now. The longer-term prize is company-specific versions that fold in local knowledge and connect to existing leakage systems. Further research into soil moisture, summer breakout and pipe age will sharpen the picture again.
Leakage is a problem the sector has worked on for decades. This project shows there is still room for sharper questions. And sharper answers.
