[denton-scratch]

> why a state might want to limit or prohibit rainwater collection

It seems nuts to me - a bit like regulating the breathing of air, or restricting the right to look at the sky.

I can only suppose that these regulations protect the revenue of water companies. I can't think of any socially-useful reason for restricting rainwater harvesting, when the rain is falling on private property.

Harvesting all the rain that falls on a floodplain is another matter; that would amount to appropriating an entire river, which in some parts of the world would cause an "international incident".