I'd like to filter, treat rain water safe enough to drink.
It's not difficult at all Wabi. Depending on how you do water collection, the cost starts around $300. The sky is the limit with water collection. If you already run a basement sump pump, and the water is available year around, there's your rain collection. $3 For a new food grade 5 gallon bucket. Pour it through a premium gravity fed purifier.and you are set. I have a couple elements from my Berkey that I have replacements for waiting. 10+ years later and still working good from the shallow well.
If you collect off of a roof, there's YouTube videos of high end catchments with IBC Tanks and pvc plumbing for the DIY. Here's a good video on acquiring them low cost if available near you.
