Using filtrated water is just as important for your plants as it is for you to drink. Plants require clean water to ensure the pH remains balanced and that no harmful toxins are being fed to the plants.
The best form of water to feed your plants is reverse osmosis water (RO). This is the separation process that uses pressure to force a solution through a membrane that retains the solute on one side and allows the pure solvent to pass to the other side.
Using RO water should keep your pH, EC, and ppm in balance but make sure to test often and adjust the pH to make sure it does not harm your plants if there is a problem'
For more information why the pH of your water is important please read about pH here.