Right now, the water is coming straight down the downspout, not being diverted. When it rained, I would let the water continue down the drain to wash off dirt/whatever from the roof, then move that part and the water would go in the barrel. I have a slate stone roof, not composition made with chemicals.
I would run the water through large coffee filters to remove any remaining dirt/particles, then put it through my Big Berkey.
We just have regular 30-year shingles. So I’m not sure how safe they are. We collect the water off the roof for watering flower beds and trees mostly during the dry season.
Just wondering if there was a way to make it potable.