Ok, so how pure does your water have to be? Do you really need RO? Will just sediment and carbon filters be good enough? I see alot of people just use ice maker filters, or one guy wrote about using the filter from a Mr. Clean car wash washer. SO how clean should your water be/

if you are on municipal water you can use the tap - just make sure to let it sit out for several hours first so that some of the extra chlorides will dissipate (the town/city floods the water supply with chlorine to kill any microbiological bacteria that can be in the lines.