Earlier quoted context omitted.
Aren't water wells permitted? In that case, you simply require a meter, ideally the cellular or zigbee sort. I'm sure there would be water bandits but it doesn't seem totally impossible.
Hang on, you want me to pay the local government for water under my land that they don't treat or pump for me? You're going to have to adjust some property laws in the US (and at least England and Canada I would guess) to do that.
Rain barrels are/were illegal in a lot of US areas because you didn’t own the water that landed on your property.