Distilled water prepared by vaporization and condensation process. pH 7.0. and TDS < 5.0 ppm, Double distilled water: when distilled water one more time distilled, pH become 5.5-6.5 and TDS reduces to 1.0 ppm. De ionized water is neutal in pH and prepared by de ionization process. TDS 1 .0 ppm. Milli Q water is prepared by Reverse Osmosis process.