Ask Coke
Are there any restaurants (or convenience stores/gas stations with a soda fountain that use your same water? Because Coke and Pepsi have stringent requirements for the water that goes into a soda fountain.
by "soda fountain" I mean that thing, where there are 6+ flavors of soda on tap, usually ice too, and you can pump basically unlimited amounts. It mixes mix concentrated syrup from cardboard cartons stored some distance away, carbonation from CO2 canisters supplied locally, and water from the tap that is filtered so minerals and water treatment chemicals don't make the soda flat or taste funny. This is why Coke tastes like Coke everywhere.
Most of those machines are actually owned by the Coca-Cola Company, and when they install one, they do water testing and dictate to the owner what kinds of water filtration they must install to get the water quality to Coke company spec. And that must feed the ice machine too. The restaurant is also welcome to hang anything else off that filter, e.g. Coffee and tea machines.
That is why, even in a town with dank tap water, the stuff from the "water" side-tap on the soda fountain tastes so good.
Anyway, the upshot is you don't need to reinvent the wheel... Just find out what's behind your nearest Coke fountain.