Yes, I use rainwater. Collecting it is no problem. Simply fit a diverter on your downspout. It works because the water actually flows down the sides of the spout, it doesn't pour down the middle.
The only problem you might have is storing sufficient quantities to see you all year round.
I can't do that (at the moment) as I live in one of the driest parts of the country. I hope to get about 5 IBCs and then I can do it.