TDS literally means completely dissolved cold substance, that is, a matter which dissolves in water. These substances are calcium, magnesium chloride, magnesium sulfate etc. They are filtered in the water we extract from inside the ground, but in surface water such as river/stream or where the water remains stagnant (lake/pond/reservoir), they are found in solid form in the water. The amount of TDS in water is measured in milligrams/litre or per million pieces. Salinity in water is mainly due to magnesium chloride, calcium and magnesium sulfate. Despite the amount of work, some dissolved solids are also very dangerous, such as arsenic, nitrate and fluoride. Some quantity of substances found in water is fixed. The World Health Organization has set certain standards in relation to water. Among them, BIAS 10500-161 is applicable in our country. Drinking water has become so polluted in our country that the quantity of substances like TDS has become much higher than the prescribed standard