Smitty
Plant Ninja
I've often thought about doing that, but I'm not certain, because of my metal gutters... I thought about testing the resulting quality with a TDS meter, but was then worried about the presence of ions that aren't detected by the meter... I might try this if it works for you... Do you test the water quality before use, or have you just found that your plants are doing fine with the water?
It rains alot here in NY! I too collect rainwater out of my aluminum gutters. I channel it right into some round garbage bins. Went to the homebrew store and bought a screw in spigot. I save my empty gallon jugs from distilled water purchases and fill them up. Nothing in the room seems to mind it all! Saves me more money for neps.