RO filters are very waste ful of water and are most wasteful if they are running for only short periods of time. The most effective way to use a RO filter is to run it long enough to fill a container full at one time, or at least for a period of hours at a time instead of minutes or seconds. With a float valve your talking about running the RO running in short spurts. You would probably use 20 to 30 gallons of water per every one gallon of water produced when running the RO filter in such short spurts. RO filters are not environmentally friendly, especially if your from a area with limited water. Even my commercial RO filter only gets one gallon of water for every 2 to 3 gallons of waste water, and is has a 2.5" x 25" inch membrane with a pump pushing water at 225 psi through the membrane. Plus it is preceded with ion tank ion exchange water softener and a 54 inch full tank carbon filter and two 20" presediment filters. Just the replacement membrane cost $325 from a wholesaler. NO I could not afford to buy it retail, I bought it from a LFS that went out of business. So I now have three RODI filter systems. Isn't that special. That is my Dana Carvey imitation.