Hydrotech Reverse Osmosis ("RO") filters most contaminants from water. It is one of the most effective forms of filtration. The Reverse Osmosis water purifier gets plumbed under your sink and has its own spigot. Add a line to plumb to your fridge water, too. You can also opt to upgrade the faucet for a designer look. Add a post-calcite filter to replace minerals lost through the hydrotech reverse osmosis process.