The idea of catching and storing the water made me think of what a buddy did at his house.

He's rural and so there are no fire hydrants anywhere near his place.

He had a giant cistern (sp.) (aka underground water tank) built and built one of his patios over it.
All the downspouts and paved areas drain into it.
I think it hold something like 60,000 gallons and it's there for the fire department to drop a hose into if there's ever a fire.

Admittedly his house did cost millions to built, from what I've been told $14 million.

Storing water for watering plants for when there are drought is a thought.

I know it's had to think about droughts when you currently getting flooded.