I don't know where else to post this so it is going under Ideas. I've been playing around with rainwater retention for over a year now. I have one rain barrel that I bought, and another that I built. I'm now working on a system that uses four 55 gallon drums piped in series with the 40 gallon unit that was store bought. In the end I'll have upwards of 300 gallons to use on the garden during our dry summers. Most of the parts have come from craigslist free stuff. The barrels are recycled from a car wash detergent wholesaler. I'll keep y'all posted with pics as the build takes place.