OP numbers aren’t only a city problem, IIRC [0] the numbers are close here in France. There’s a startup that try to tackle it : www.leakmited.com/en I applied there 3 month ago and they never responded. Can’t blame them but I’m a bit sad: it’s the dream impact-job.

[0] 20% apparently https://www.eaufrance.fr/repere-rendement-des-reseaux-deau-p...

I wouldn’t be too sad. There are lots of companies offering ML leak detection. Most or many are using fibre optics and using them to detect changes in temperature or noise along the line. Sample the signal for period of time and run it through a model and you have leak detection.

Good catch. I mentioned it to one my wife’s former coworkers and he laughed - I guess our city is in particularly good shape. Mea culpa.