Are rain barrels a wise use of money for Californians, specifically the most populous places like SoCal and the Bay Area)? A 55 gallon barrel costs $100. For us, 1 ccf (750 gallons) of water costs something ridiculous like $4. So that barrel would have to be filled up 13+ times to equal one ccf. At $4 per ccf, we would have to fill it up 325 times to break even. That's a long time for most anybody.
However, it's particularly unappealing in places that have the rain, even though this is where it would be most useful. Why? Well, take us for example. In most parts of California, it doesn't rain between May and October. It rains off and on for the rest of the winter/spring, usually frequently enough that we wouldn't have to water any plants during those months. So for several months we have sufficient rain that we wouldn't need the rain barrel, and yet we don't have rain when the plants are most wanting for precip and therefore the barrel would sit empty. Therefore, the barrel would only be useful maybe a few times a year.
I realize there are environmental reasons for using rain barrels. We are super conservative with water, using 2-5 ccf per month with a family of four, a huge property with lots of veggie plants and young fruit trees. We divert a lot of our grey water to the trees and native plants.
The background is that we own our home in the Bay Area and are re-doing our landscaping. The lawn has been removed and in it's place are ten fruit trees, tons of gardening area, and native plants. We worked with a local husband&wife team who advise on plan these transitions, though we are doing the work ourselves. They seemed really keen on rain barrels. It wasn't until I did the math and thought about how many times a rain barrel would actually be useful, that I started doubted the advice. The math is less worse if we get a giant water storage unit that can hold 800-2000 gallons.
I bring up this question in hope to hear other thoughts on the matter, like when and where rain barrels work best. And why we might still consider them. What am I missing? Thanks!