Hi Wayne,
We’ve used the rainwater for lacto-fermentation (preserving vegetables like green beans without heat processing), for hot water in our wood stove, and for watering gardens and the greenhouse. I’ve had a cup or two of the water myself and found it delicious, but I did filter it first because algae tends to grow in the above ground tanks.
Before I set the system up, I check the NSF website which indicated that rainwater, even collected from an asphalt shingle roof, should be ok but they recommended filtering it first.
I have no problems drinking the rainwater, frankly, but right now it’s easier and more convenient to drink well water out of the tap. In the future, we’re likely to drink quite a bit of rainwater, particularly in the case of extended power outages.
Back to the lacto-fermentation of vegetables, our experience is that rainwater works better than well water. Even for heat processed canning the rainwater is superior.
Larry