You don’t. You have RO at the point of consumption. At any rate, it’s our approach, we store 150,000L in a cistern over the winter and use it through the summer

You don’t. You have RO at the point of consumption. At any rate, it’s our approach, we store 150,000L in a cistern over the winter and use it through the summer. An under-the-counter domestic RO system can be had for like $200, the membranes last about a year with our usage, and are like $15 a pop. Post-RO storage tank UV block too because I like belts and braces. Non-potable just goes through the usual barrels full of sand and biochar, and doesn’t need further treatment.