From a friend in germany last spring... just sharing.

More garden in Germany photos.

Here's my old rainwater collection for watering the rabbits. That slanted pipe has a coke bottle in it with a little ballast. That way as the first rain falls into the slanted pipe and fills up, the bottle floats up to the choke point. This seals off the bottom part and now water flows out the Y toward the 55gallon drum for rabbit water.

Yes, this was at my other house. It was a lean to behind my workshop.