I just pick up an under the sink reverse osmosis system for $150 from Lowes. The kit came with everything for the install including a purge valve to tap into a cold water copper pipe. I thought I was getting into a full day project, rather being installed in 45min. The replacement filters seemed expensive at first. However, they run about $60 and require replacment every 6 months. So $10 a month for RO water is a no-brainer.