For the water business, many people are living off cisterns in the world. I understand that Tortola in the BVI now has a water supply for most of the islands, but has not yet removed the cistern requirement from their building code (again, just heresay).
Building a cistern is not foolproof, as concrete cracks, and it doesn't take much of a crack to cause trouble. Also, liners typically cause taste problems, especially when mixed with chlorination - which I would recommend.
If you can make a good concrete cistern, with extra reinforcement and proper attention to the water to cement ratio, you can avoid the cracks, especially if there are no freeze-thaw cycles and if there is proper compaction. If cracks still show up, epoxy
injection grouting can now be used to seal them.
Find a way to run gutters and collectors into the cistern, but with bypasses to get rid of the first wash. I would stick to a gravity system. You might consider a double cistern that would allow skimming, settling, and pumping through a cheap
ceramic filter before the potable second half of the system. The second cistern would have rather pure water in it, and would be easy to keep slightly chlorinated. Chlorine would keep it sweet, and with extremely low concentrations of organics, you would have no chlorinous taste or odour. Keep the water above 0.3 parts
per million, using appropriate sodium hypochlorite or calcium hypochlorite purchased for the job.
I am unsure about the pH of rainwater. If it is too low, you may have copper and lead leaching. Plastic pipe for plumbing
is now in vogue anyway.
As for pumping, marine
stores can easily provide you with 12 volt pumping systems and expansion tanks
. If you go that route
, I would still suggest at least one location in the house be set up with a manual pump system for when these sometimes troublesome little buggers refuse to work.