Rain recycler

I've been trying to brew as green as I can and I hate how much water I let run down into the drain when using my wort chiller.

Here's what I came up with. I got a rain barrel, drilled a 3/4 inch hole, stuck a 3/4 inch barb in it, and attached a hose bib to the barb.

I then (after I drilled the hole) asked a science teacher at my school if it would work...he laughed at me and said it wouldn't, not without a pump :) Oh well, I guess that's why I teach English. The only thing I haven't figured out is what to do in the summer, but I've got 4 months to think of something.