Joe, of Homesteadonomics, who is located out in Arizona has done a really nice job of designing, installing and living off a rainwater harvesting system for he and his family. This video gives a detailed tour of his system. The following video is a Q and A on his system.
Granbury, Texas, where Texas Tiny Homes is planning to build some small luxury homes, averages around 35" inches of rainfall each year. Adding a rain-harvest system to supply all the water needs for our homes is possible, but would require some planning and the upfront expense to design and install a system. Examples: A 14' X 25' carport (one of the options for our new homes) could capture around 7656 gallons of water per year based on the rainfall in Granbury. The roof on one of our 600+ square models could capture another 5000 to 7000 gallons of water each year, so both roof capture scenario's could provide all the water needs for the year for one person living in one of our small homes. The rain water would be treated and filtered, meet health department requirements, but could save you $700 to $1000 dollars per year in water expensive. The upfront expense for a rainwater harvest system for this size would run approximately $4500.00; including materials and installation, but would pay for itself in 5 to 6 years. A rainwater harvest system is something to consider if you wish to live off grid, organically. All of our lots in Granbury have metered water available from a community water system for those not interested in this approach, or unable to afford the upfront expense