Luke Butler

Luke Butler did not set out to spend his life on water networks. As he tells it, you are 16 or 17, you are doing all the maths and science, so you do engineering, and it turns out half your family did too, so maybe it was a wise choice. His dad was a software programmer, which is where Luke says he got the coding skills that now define his work, and a chance friendship in a study group with someone at a water utility nudged him toward the field. He started in hydraulic modeling in Australia and, by his own admission, did not love it, until he moved to the UK and discovered a whole other, far more advanced world of water-network modeling, and that is where, as he puts it, his love for it finally blossomed.

Luke Butler builds and breaks down a thing called hydraulic modeling, which is worth decoding because it sits under everything he does. A hydraulic model is a computer simulation of a water network, the pressurized clean-water pipes or the wastewater drains, that lets a utility ask what-if questions: what happens to pressure and flow if I add capacity here, or shut a tank there. Luke describes it as looking a bit like Google Maps with the water layout drawn on, while behind the screen large matrix calculations crunch the numbers. The reason it matters is that a utility can have thousands of kilometres of mains and only a handful of sensors, so the model is often the only real visibility it has into what is actually happening underground.

Luke Butler's whole argument, the one he came on the show to make in 2021, is that the bottleneck is the software, not the engineering. Open up a traditional hydraulic modeling platform for the first time, he says, and you are faced with literally a hundred buttons and cryptic menus, and when something goes wrong it throws back a big red error screen, so the tool ends up needing a trained specialist and gets pulled off the shelf only every five years to write a long-term plan, then put back. The operators understand the hydraulics, often better than the engineers, but the software lets them down. So at Qatium, the digital-twin platform he had joined about five months before we spoke, he led with a line from one of his conference slides that he is rightly proud of: big or small, digital twins accessible for all.

Luke Butler kept pointing, in that interview, at a piece of open-source software of his own that quietly powered the whole pitch. The heavy hydraulic simulations, which are normally computer-intensive and data-hungry, ran locally on the user's own machine instead of on big servers, which he said dropped the cost of hosting them to fractions of a cent and underwrote the free, freemium business model. That software is epanet-js, his project to compile EPANET, the free public-domain modeling engine from the US Environmental Protection Agency, so it runs straight in a web browser with no download. It is the through-line of his career, the same local-first, open-source engine that sat under Qatium and now sits under his own company.

Luke Butler has since taken that engine and made it the whole point. He has left Qatium, and as of 2026 he co-founds Iterating, the Toronto startup whose product, epanet-js, lets anyone start water modeling in the browser, free, no download, the literal version of the accessibility he was preaching back in 2021. The thread is openness, which is genuinely how he operates. He told me he enjoys doing things out loud, sharing the work warts and all, because he thinks the water industry is at its best when everyone shares what they do, and that instinct, plus a steady stream of open-source posts, has built him an audience of more than ten thousand on LinkedIn. There is even a neat personal tell underneath it: he only realised, he said, how much free time he had to build open-source apps for fun once his daughter was born and that time vanished, a lesson he learned the hard way.

“I always wanted to tell everyone the truth, warts and all. Okay, this is how it's done. And open source was just one of those ways that I did it.”

That openness is the spine of the whole story, the reason a hydraulic modeller who did not even mean to end up in water now spends his days giving the tools away for free.