I still use http://seductiveequations.com/2015/11/09/water-meter.html rather often to casually see how much water I've been using. Helped me to discover when a new water timer I installed outside got stuck open. Similarly, I've been able to see through actual data how much water my new low-flow showerhead just saved me right after I step out of the shower. Wish I had more time to improve it, but despite that, it's still remained quite useful.