Portsmouth, Rio de Janeiro, Oman, Limburg and Milan. What HULO found, including the results that missed their target and the ones nobody has measured yet.
Every figure here comes from a document a customer has seen. Where a target was agreed, results outside it are reported as misses. Where nothing has been measured and agreed, no number appears at all.

The hardest starting conditions of any deployment here, and the tightest result of any deployment here. Delivered with Witteveen+Bos and BlueGold Technology.
The ground a crew has to cover. It holds six tenths of one per cent of the mains in the zone, so 99.4% of them are never walked.
From system activation to the first detected event.
Measured, not estimated from a water balance.
Pressure sensors actually working in the region.
One functioning pressure sensor out of five installed. District metered areas that could not be isolated. Problems inside the reservoirs, including float valves found disconnected. A network topology that resisted straightforward monitoring.
Nothing was added to fix it. Sensor positions were chosen using control-systems engineering rather than convenience, eighteen locations, and integrated with the existing SCADA.
Any vendor can show a good result on a well-instrumented network. Oman is the opposite: the worst starting conditions on this page produced the tightest localisation on this page.
The argument running through this whole site. That the signal is usually already there and simply is not being read, is easy to dismiss until you watch it work on a network where four sensors in five were dead.


The largest test of the argument on this website, in a network with no district metered areas at all, and no plan to build any. Presented on stage by HULO and Aegea together, which is the only reason these numbers are publishable.
One in ten leaks found at the start of the programme. Nine in ten by the end.
Often 200 to 600 metres, in Aegea's own account of the field work.
From event to a prioritised area a crew can be sent to.
Fewer sensors, not more. Repositioned and repaired rather than added to.
Hundreds of sensors, data available, real ambition. And underneath: some sensors not working, some installed somewhere other than where the records said, some reporting once a day. Search areas running to 500 kilometres.
“More data did not solve the problem. Better understanding did.” Robbert Lodewijks, CEO and co-founder, said that on stage in Rio. And from Aegea, in their own words: more sensors do not guarantee better results; understanding your network does.
These results come from controlled tests, not real leaks. Moving to live events and scaling across the network is the next phase. We would rather say that here than have you discover it in a reference call.
Águas do Rio operates without DMAs and does not intend to build them. That is exactly why this test matters: it asks whether a utility can gain visibility without restructuring the network first. On controlled events, the answer was yes.

Portsmouth opened ten hydrants at locations they did not disclose, across two areas, under deliberately varied conditions, one with a logger missing, two overlapping, one timed to collide with the morning demand rise.
Across both areas, flushes that landed inside the search area Portsmouth agreed beforehand: no larger than a quarter of the main area. Four of the five at Binsted Ford. These are the results from the data; read the limitation below for what that means in real time.
Of the main area, at Binsted Ford: a 98.6% reduction in ground to cover. The others in that area came in at 7.5%, 13.6% and a very small zone.
The one flush of the ten that missed, with a second candidate area about 500 m away.
Controlled flush testing is phase three of five, not the end goal.
At Yapton, one flush localised correctly even though a pressure logger had been removed by mistake before the test. Two flushes thirty minutes apart in a shared window were both captured, and as it happened one of the two could not be told apart from the other. In the data afterwards it could. That is the honest shape of these tests: they were deliberately messy, and separating them live is harder than separating them later.
That one is worth understanding rather than explaining away: a ninety-minute flush timed into the morning consumption rise looks like the morning consumption rise. A real leak does not stop after ninety minutes. It persists, and stays visible once the rise settles.
Four of the Binsted Ford flushes ran back to back overnight. In real time HULO captured them as one long combined event, not four. The individual accuracies above come from separating that event afterwards and re-running the analysis per flush.
So read them correctly: they show the localisation model is accurate, and that real-time event separation was the weakness when interventions land minutes apart in the same neighbourhood. Only the fifth flush, which stood alone, was both detected and localised live.
Bob Taylor, CEO, Portsmouth Water
Two engagements where the work is real and the measurement is not finished. They appear here anyway, because leaving them off would be its own kind of dishonesty, and they appear without figures, because none have been agreed.
WML · Limburg, The Netherlands Public utilities do not endorse vendors. What WML will say is what the work is for: an additional analytical layer on the operational data they already collect, supporting the people who interpret it.
Rolf Cuijpers, process operator, Waterleidingmaatschappij Limburg
Gruppo CAP · Milan, Italy Italy spent its recovery-fund money well: sensors, district metering, digital infrastructure, data collection. Gruppo CAP now has an instrumented network and the question every utility reaches next, what does all of it actually tell us on a Tuesday morning?
At assessment stage: anomalies detected on the existing network and validated against what the field found.
Most markets have to be persuaded to invest in visibility first. Italian utilities already have. The gap that remains is not more measurement. It is understanding what has been measured. NIS2 has also been enforced there since October 2024.
Nine results on this page went well. Two did not. Both are here, in the same type, because a page you can only agree with is not evidence.
Leakage is where a utility starts with us, because it is urgent and it is measurable. It is not where HULO stops. Everything below is already running on the wider Portsmouth network, outside the controlled tests, on real behaviour. It is also what the Rio deployment with Aegea and Águas do Rio runs on day to day, and what the Milan engagement is scoped around.
NOT A ROADMAP, NOT A PROMISE, AND NOT SOMETHING WE NEEDED A CONTROLLED TEST TO DEMONSTRATE.
This is the difference between a leak detection tool and an intelligence layer.
A tool answers one question. A layer answers the question you had, and then the two you had not thought to ask, because it is reading the same network, continuously, with a model of how it ought to behave.
It is also why the sensor health work matters as much as the detection work.
Software that cannot tell you where it is blind is not giving you intelligence.
It is giving you output.
Fewer than you would expect, and more of them buys you a smaller search area. Six zones we run, from one sensor every 41 kilometres to one every 3.6, with the area a crew was given at the end of it. Every one of them detected, classified and localised in under fifteen minutes.
| Where | Setup | Sensors | Network | One sensor per | Search area | Of the network |
|---|---|---|---|---|---|---|
| The Netherlands | Open network | 1 flow · 10 pressure | 450 km | 41 km | 900 × 900 m | 1% |
| Latin America | Open network | 2 flow · 17 pressure | 321 km | 17 km | 500 × 500 m | 0.8% |
| Italy | Pressure zone | 3 flow · 16 pressure | 203 km | 11 km | 500 × 400 m | 0.6% |
| The Netherlands | Pressure zone | 4 flow · 18 pressure | 100 km | 4.5 km | 200 × 200 m | 0.2% |
| Italy | DMA | 3 flow · 3 pressure | 25 km | 4.2 km | 400 × 200 m | 0.6% |
| Middle East | DMA | 2 flow · 16 pressure | 65 km | 3.6 km | 250 × 250 m | 0.6% |
The sparsest zone in this table carries one sensor for every 41 kilometres of main, and it still put a crew inside a 900 metre square. Nothing here needed a network to be instrumented first. What the closer spacing buys is a smaller box: at one sensor every four kilometres it is 200 metres, which is a street rather than a neighbourhood.
Which of those is right for you is a question about what a search costs you, not about what the software needs. The feasibility scan answers it on your own network, and where the instrumentation cannot carry what you want, it says so before you sign anything.
A hydraulic model is enough to begin. Give us the model and no measurements at all, and the first thing HULO answers is not where the leaks are — it is where the sensors should go to find them. That is a smaller, cheaper question than instrumenting a network and hoping.
A utility deciding on continuous monitoring needs the limits more than the wins. Both are here, in the same size type.
What we found, on which network, and what it cost to find it. Roughly monthly, and never a figure we cannot show you the working for.







HULO’s project Lekker (tegen lekken) is co-financed by the European Union, by SNN and by the Dutch Ministry of Economic Affairs.