sentences:  The most accurate way to measure all TDS in water in a laboratory is to evaporate the water leaving behind dissolved solutes as residue, and then weighing the residue.Many TDS meters display the TDS in parts per million (ppm); 1 ppm indicates 1 milligram of dissolved solids per kilogram of water.The terms EC and TDS are both often used to quantify the amount of dissolved solids in water.