What is tds

Understanding TDS

Total Dissolved Solids (TDS) refers to the concentration of inorganic and organic substances dissolved in water. These dissolved substances include minerals, salts, ions, and other compounds that have dissolved completely and remain suspended in water rather than settling as sediment. TDS is an important water quality parameter measured in milligrams per liter (mg/L) or parts per million (ppm).

What Causes TDS in Water?

TDS levels increase naturally as water passes through soil and rock formations. Minerals like calcium, magnesium, sodium, potassium, and carbonates dissolve into groundwater. Additionally, TDS increases from human activities including agricultural runoff, industrial discharge, and urban pollution. The geological composition of an area heavily influences the natural TDS content of water sources.

How TDS is Measured

TDS is typically measured using electronic meters called TDS meters or conductivity meters. These devices measure the electrical conductivity of water, which correlates to total dissolved mineral concentration. Distilled water has a TDS reading near zero, while seawater has TDS readings around 35,000 mg/L.

Acceptable TDS Levels

Different applications have different acceptable TDS levels. Drinking water standards typically recommend TDS below 500 mg/L. The World Health Organization notes that water with TDS above 1,200 mg/L may be unpalatable to many consumers. For specific applications like aquariums, humidifiers, and industrial processes, even lower TDS levels are required.

Health and Practical Implications

While dissolved minerals are not inherently harmful and some minerals are beneficial for health, excessively high TDS can affect water taste, appearance, and suitability for various uses. Water softening systems, reverse osmosis filters, and distillation are common methods to reduce TDS when necessary.