When my brother built his home he used his water treatment knowledge to use the rainwater from his cistern for drinking as well.
I offered to finance a business where he could deliver potable water at a cost cheaper than the $50/jug price but he didn't see the profitability so he demurred. Of course he has a nice large lot and planted coffee trees which means he doesn't have to go to Starbucks!!!
Just to help (or maybe what you wrote was deliberate, if so, sorry)
Mauna Kea -- big extinct volcano with astronomical observatories on top; world's highest mountain from base to peak.
Mauna Loa -- big still-active volcano (and we're waiting for the next proof of its activity; its overdue)