@BowsacNoodle very cool idea. I just moved to cistern country and am going with rainwater collection treated for potability to solve this problem. I am going to Strongly consider this.

the energy usage reduction here is great, but the cost of filters at the schedule proposed might be a net negative. hard to figure the math off the cuff.

rainwater has a lot of passive filtration options, and you aren't dumping a lot of soap and stuff into it.

I'm at a disadvantage energy wise, because the layout ofy property requires any collected rainwater to be pumped, but a pure gravity fed rainwater collection system is probably better cost wise. for me it's probably a toss up.

might install one as a hybrid just to be safe for power outages, etc.

very interesting, regardless. hard to believe ideas like this are "fresh" but here we are.