And I very much agree RO water is only necessary in some grow rooms. A simple filtration would be good for most water.
Though, I have taken the time to show that in 90% of the cities that had their municipal water tested failed the hexavalent chromium safe levels. San Jose, CA was over by 3000% the "safe" value. This shit gives people fucking cancer. No lie. It is also well known that reclaimed water contains things like asprin, birth control hormones, heavy metal, pesticides and fertilizers.
It is just a matter of being educated and knowing where your water is coming from. Personally, I won't drink sewer "water" that "the man" has treated and told me is totally safe to drink. It is one of many reasons I chose to live where I live. Water is life. The disconnection from nature is a huge issue with America and it is demonstrated in our water. If you are what you eat, and you are 60% water... Do you really want to be 60% filtered piss mixed with reservoir water?
Again, not everyone needs a filter, but for those that do... I feel sorry for you.
Hell, home delivery water services are EXTREMELY affordable in large cities if you don't want to sack up and install a big filter. There's always a way and it's not like the water from the tap is free. My water/sewer bill is like $50 a month up here in Oregon and I don't have to throw away any water for filtration.
You're dead right, I can't imagine what a large operation might cost, but I'm sure the energy bill isn't cheap either...