If you’d like to get some hard data on your water usage, have a look at [Josh EJ]’s Sensible Flow project. It contains designs for a set of sensors ... a power-efficient Arduino Pro Mini ...

This is a simple arduino project for a soil moisture sensor that will light up a LED at a certain moisture ... in the dry soil and measure the resistance value and then pour water and measure it again ...

It runs on an Arduino MEGA 2560 PRO (or similar microcontroller) and supports a wide array of additional hardware including pressure transducer, water level sensor, flow meter, OLED display ...