This really depends on how good your tap water is.I live right on lake Michigan,and our tap water comes right out of the "big pond".Filtered of corse.It is possibly the best tapwater in the country(at least that is what our local culligan man says). But I have never used anything but my tap,and never had any water related problems.You can contact your local Culligan rep and they will do a full spectrum test on your tapwater for free.Then you will know if there are any problems with it...If there is anything bad in it,then a RO/DI unit can be purchased,or rented directly from them for about 25 bucks a month.They do all the maintenance.Including cleaning,and replacing filters when needed...
