[mike31154]

RODI systems run between $150-200 and much higher depending on how many bells & whistles. Those commonly used in the hobby are in the $200 range and are not whole house. They will have one or two sediment filters, a carbon stage (perhaps 2 if your water is treated with chloramine), an RO membrane stage & finally a DI stage. Water softener may not be needed, again, find out more about your source water first. Best to look for a RODI unit on line, the local hardware stores charge much more & generally aren't able to provide customized set ups.

Many of us put a T fitting before the DI stage & make RO water for day to day use, coffee, cooking, wine/beer making, ice cubes and so on. Some RO systems include a small pressure tank & a small tap for pure drinking water, but these add complexity & cost to the system. This makes the system cycle often causing premature fouling of the RO membrane. Longer runs of the system (minimum 5 gallons) are much better. I find filling a standard water jug with RO water when I run the system a great way to have fresh water for household use on hand.