Hi Joe and Welcome (and happy New Year)!
I've heard their are places where a 'rainwater collection system' would be against the law.
It might be good to pre-check the local ordinances.
Since I live about 75 yards from a pond and have a swamp bordering on my backyard,
I've been thinking about digging a small well to use for watering the lawn.
Years ago, I used to drive by a company that always had sprinklers going
in the middle of dry summers.
Then one day they put up a big sign saying it was "Well Water"..