I have a simple set up for RV rainwater collection off the roof of the motorhome while boondocking. During a recent desert storm, that lasted half a day, I collected around 25 gallons in 6 blue buckets. I could have collected more if I had the storage!
After collecting the run off, I filter it through a ceramic gravity fed filter. I’ve changed it since the video, from a Katadyn filter to a Zen filter, because the Zen filter has a lower profile, making it better for stacking the blue buckets into the white 5 gallon buckets for storage. It also is impregnated with silver, to kill bacteria.
The ceramic gravity filters can take a long time to drip-feed; one Zen filter is taking more than 24 hours to filter 5 gallons. The solution to that would be to add more filters; drill holes for 3-4 filters, instead of one.