I haven't found that to be the case.

https://www.amazon.com/Whirlpool-WHER25-Reverse-Osmosis-Filt... that is $130 and the kits are very easy to install. In 13 months you'd have it paid off and you can make all the water you want.

They've definitely come down in price but you're still talking 130 + installation + $80 in filters per year + leak potential. It's almost break even. Unfortunately there's still the problem that my wife being from a 3rd world country won't drink anything out of the tap that hasn't been boiled no matter how much it's been filtered due to no rational reason.

Basic systems will waste 4 gallons of water for every gallon of purified water depending on input pressure and temperature. Lower input temperature and pressure will increase waste and lower output.