We are using trash barrels. We have 1" hose to siphon from one to the next. Once one is full we remove the siphon hose and put on the lid to prevent mosquito larva. So far, we water by scooping it out with buckets and hand-carrying it around the yard. Low tech and low cost, but labor intensive! The one directly under the downspout gets emptied as soon as we see larva in there, since we can't make a tight seal around the downspout--at least in our low/no-cost, low tech mode. Since the downspout is right next to the basement window where the washer is, we often siphon the water directly into the washer. If I've used rain water for the laundry, I don't feel guilty using hose water for the garden. Despite having a moderate size garden, including many flowers, our water bill is never over the minimum. (This is OT, but minimum water billing certainly is a disincentive for water conservation, However I do see how everyone has to chip in for maintaining the infrastructure.) My latest brainwave is to get permission to hook up some of that black downspout extender to my neighbors downspout, which is just a few feet from one of my flower beds. Good for them as it gets the water further away from their foundation. Good for us because it's more free water. My neighbors have already decided I am odd but harmless, so this won't make things any worse!

Bon, In your case with the open top container, I would put fish in the tank. Even if gold fish is all you can afford, they will take care of the mosquito larvae. Bird poop, that's a good thing. Soap may be hard to rinse out, but I think it can be done. If your water could run through a tank of sand on it's way to the garden, I would think it would remove most things. I think most things coming off the roof are going to end up in the ground anyway, so short of lead, it probably isn't going to matter. While I wouldn't like roof particles in my garden beds, in the long run it probably isn't going to hurt the soil. After all, it came from the earth originally. This is a quote from an article written by Geoff Lawton who teaches and designs restoration projects all over the world. The Bill Mollison that he speaks of is "the King" of permaculture, and wrote the book that has become the permaculture 'Bible'. Here is the quote: "We also looked at the spraying of oil residues and oil waste products over sand dunes which is a system proposed by Bill Mollison in the first Gulf War in Kuwait, where oil wells that were destroyed and were causing a lot of pollution across the landscape. These oil residues and surplus oil waste products can be used to spray sand dunes after they have been seeded to rehabilitation species and pioneer sand dune stabilisation species." I am not suggesting that it would be safe for food, but in the long term it was removed from the earth and returned to the earth so I wouldn't be concerned about what falls off the roof onto the ground, but I wouldn't want it directly on my food plants unless it was run through a filtering area first.

I have the same rain barrels that greenleaf has, from AustinGreenWater. They are great! They have a mesh screen over the hole in the top where the water goes in. the screen holes are like screen door screen, VERY tiny. Thus, mosquitoes can't get inside to breed. However, the company said that it may be possible for some eggs to be washed into the barrel with the water, but the screen is so tiny that if a mosquito hatches in the barrel, it can't get out. Sounds reasonable to me. The barrels work great!

wow! thanks for all the replies. The corners sound like a great idea. The reason the right one is further over is that there is actually a wall there, they probably wanted to get to the other side of the wall. I'm planning on putting a small fountain inside that wall. But I could actually put my rain barrel on the inside of the wall, the downspout coming down the corner into it, then use the fountain to hide the rain barrel. I'll have to see if there's enough room for that. I could route that overflow into the garden to the right. The left down spout can go to the garden on the left, I never really even thought about that. This place had some serious drainage problems when I first moved in. In the first big storm, one whole side of the house was flooded. So I built this: There is a french drain under all that rock. It was a fun (laborous) project. I could route the left downspout into an underground pipe that goes to the french drain.... Speaking of downspouts. Don't you love how the one in that pic terminates right inside the garden edging. I never noticed that - guess I need to fix that too, huh?