If you're going to use an RO machine, make sure to get a good sea salt (Himalayan pink, Celtic, etc.) and add some of that back to the filtered water.
Pure water without any minerals (your end product after running water through an RO machine) acts as a solvent in your body and strips minerals out. Not good at all for your health.
Using RO is fine as long as you add sea salt back to the filtered water. Get yourself a cheap handheld TDS (total dissolved solids) meter and add enough salt to bring the TDS up to at least 125 and up to 400'ish PPM (parts per million).