Is 20 TDS water good for you? Is 20 TDs RO water is good to drink? - Quora A Total Dissolved Solids (TDS) level of 20 ppm (parts per million) in water is generally considered safe for drinking. TDS represents the combined content of water's minerals, salts, and other dissolved substances. Drinking water with a TDS of 20 ppm is considered low and unlikely to have adverse health effects.