Simplicity is the best thing most of the time.
I have one rain barrel to water the garden that just sits out in the open, and it still stays nearly full. Well this summer it did.
For drinking and washing I just set some buckets under the eaves. I have plenty of water. I run this through Berkey for drinking.
My Grandma had a cistern, That might make sense for a permanent abode.
RE: Water Collection System for the Meadows & Makers Challenge and Earthdeeds