The filter costs...exactly why I won't go to reverse osmosis. The filters will break the damned bank. I'll trek down to the pond when I have to. Walking and carrying is free. We like free....I use a zero water pitcher because we have lead in our water because of the City pipes but it removes the chlorine too. Still even if I use straight tap water it doesn’t hurt the plants. Maybe it even helps with the micro nutrients. lol CL Edit: City was kind enough to give us the pitcher only thing is it’s 30 bucks for 2 replacement filters.