Richard's Rainwater has made an apparently profitable business out of selling rainwater harvesting systems. They have a great site, with lots of interesting tidbits:

How much can I collect?
A one-inch rain on 1000 square feet of collection surface will yield about 550 real world gallons of rainwater.

How much does it cost?
A very, very ballpark figure is $10,000 for a 10,000-gallon whole-house system including storage tank, prefiltration, pump, secondary filtration and disinfection.

You can even read the first chapter of their how-to manual, Rainwater Collection for the Mechanically Challenged, for free.

(Thanks, Triple Pundit!)

These systems should be mandatory for new homes in dry places out West.

Posted by: Stefan Jones on May 26, 2005 5:05 PM

I've been using one of Rich's rainwater collection systems for about 6 years; it works great.
Depending on rain, of course. However, last year was so wet near Austin that I never bought water at all; all the water we used came from the sky.

-jsq

Posted by: John S. Quarterman on May 30, 2005 3:42 PM

If you use a rainwater collector to collect drinking water be sure to check on it often. Nothing like finding a dead thing floating in the tank to ruin your day even if your filter system and floride/ozone made it safe...

Also be careful that pure rainwater is actauly bad for you as is pure demineralized water from any source. While not deadly its not recomended for constant use.

Posted by: wintermane on June 1, 2005 6:36 AM