I installed a 5 stage Reverse Osmosis system ( $150.00 with extra filters) under my kitchen cabinet because the treated lake water we get is horrible and sometimes comes thru untreated. The RO unit gives me Clean pure (99.99%) chemical and organic free water for drinking, cooking and Coffee, Since it only needs water pressure to work and has a 3 gal storage /pressure tank , I bought a 65 psi RV 12 v automatic water pump , the fittings, and a used food grade 250 gal plastic tank that is in a metal cage to be able to collect rain water , or fill with buckets from a spring or lake that is outside next to the house. I have a 12v Deep Cycle battery , and a 40w solar panel to keep it charged , and all I have to do is drill a 5/16" hole thru the wall and run the plastic RO supply tube outside to the RV Pump , which will be mounted on the outside wall , plumb it to the tank with a garden hose, hook up the power and I can make up to 50 gallons per day of Pure water , on a stand alone power system that solar recharges.
We keep 1 gal water jugs full stored in a closet now in case of a water line break as it may be a few hours or a day or so to fix a broken main line at the water company. We also fill our own small drinking water bottles for pennies.
Rich