Originally Posted By: Susan

If you have a 2000 sf home and a 500 sf garage, that totals 2500 sf and can produce 1,550 gallons of water. If you get 15" of rain per year, that's 23,250 gallons per year, almost 16 gallons of water per person per day for a family of four. Seattle averages 37" of rain a year, 57,350 gallons.


Rainwater collection is a wonderful idea (seriously). If you have space. And money. A ~22,000 gallon galvanized tank will run you $18,000 to $20,000 just for the tank (no foundation or install). It'll be about 19 feet in diameter and around 12 feet tall. A ~55,000 gallon galvanized tank will run you $34,000 just for the tank. It'll take up 24 feet diameter and be around 15 feet tall. Only you'd need a much rounder and lower tanks to get your roof water into it. And a pump to get water pressure out of it. And some form of sand filter at a minimum for filtration. And a big gun to keep your neighbors away from that big silver tank full of cool water.

Long term: move is the option with highest survivability. Climate change will generally make those cities with poor water availability worse off.