Rather than reinvent the wheel, I thought I'd see who already had the best ideas on this subject linked. I'm living in the Pacific Northwest, and we get a substantial amount of rainfall here every year. Like many areas nationwide, untreated stormwater runoff has become a major issue, and we are billed for stormwater treatment as a percentage of our water bill. It adds up significantly when we have to resort to using our sprinklers, which are currently fed with City water. I am ready to do a small rainwater recovery demonstration project here, that initially will provide a water supply for the drip irrigation system that waters our kitchen garden. I want it to be 55 gallon plastic barrel based, and I intend to install a new length of gutter on the back roof of my shop to catch rainwater and divert it into the barrel. I'm looking for resources that show a number of things: ** Best way to route the gutters into the top of the barrel. ** Best leakproof method for tapping the bottom of a plastic barrel ** Best method for connecting additional (expansion) barrels ** Best pre-filtering method ** Projects that show how to re-pipe your house in an emergency in order to utilize captured rainwater ** Above ground, barrel based cistern projects ** Methods of freeze prevention Of course, the object is to build a small project that identifies the considerations for eventually assembling a larger system that would capture and recycle all of the rainwater from my roof. If we can completely disconnect our downspouts from the Storm Sewers here, the savings on our waterbill would more than pay for the supplies we would need for the system. Barrels are easy to find here, and I have already identified several sources for good condition, clean, used plastic barrels. I've been plumbing with PVC for decades and I have no problem plumbing this. I realize that many folks object to the use of plastic barrels, but in this application I don't. Now it's a matter of finding the best design that will also be flexible enough to be converted to an emergency drinking water supply should things ever go really wrong.