I was a bit disconcerted when my local hardware supply store thought I was a bit daft wanting to add a cut-off valve to my shower riser (home made for a claw foot tub).

I can't wait to see their responses when I go back to get flow meters to monitor with my Arduino...

Probably my being a geek on his own well has a bit to do with my mindset. Repairing the pump was one of my first home repair jobs upon moving here, so I am frequently listening to the pump, waiting for it to cycle back off again. A stuck, running toilet once ran it dry... Hence the desire for monitoring.