When I had an undersink RO unit (back in N Virginia because the water absolutely sucked there), I used the water for my plants, drinking, and cleaning. Never had a problem. It's actually fantastic for cleaning- I cut the amount of chemicals I used for cleaning by 75% at least because I didn't need them. My plants seemed fine- really happy with it, actually, which I attributed to the lack of chlorine, lead, copper, and other crap in the water. I have a bamboo plant that's at least 6' tall now, and has grown new sprouts recently, that started as 8" sticks from the import store.