robtillaart:
For the average you might use - Arduino Playground - HomePage -However looking at the problem you not only want to detect an higher average daily use, but also a sustained flow of longer than lets say an hour should cause a "code orange" alert, you don't want a leak to flow for several hours ...
Ah yes, that's what I'm looking for, thanks!
Regards to the high sustained flow...I don't think it will be overly effective, as in peak times(morning and evenings - showers for over 1000 guests), the peak flow would be considerably high, making any water leak a small percentage, and triggering false alarms. However, I will keep it in mind. It might even be worthwhile doing some logging to find total peak flows at certain times of the day...maybe when I have a bit more experience!
Cheers,
Jason