Total dissolved Solids TDS

Total dissolved solids (TDS) in drinking water

Is  TDS is a poor measure of water quality?

No, all TDS are not bad. That’s why you should never assume water with allowable levels of TDS is polluted or unsafe to drink, nor that water with zero TDS is the gold standard for quality and cleanliness (more on that later).

Because TDS meters measure the conductivity of water, they only detect dissolved solids that conduct electricity. In other words, they detect charged solids like electrolytes—not all contaminants. The TDS meter then converts the conductivity measurement into a concentration measurement of parts per million (ppm) or milligrams per liter (mg/l) to serve as an estimate of TDS levels.

The bottom line is TDS meters provide an estimate of TDS based on electrical conductivity of water—they do not detect all contaminants, nor provide a flawless or complete measure of each dissolved solid. In fact, they will detect and register beneficial electrolytes and certain minerals as dissolved solids.

TDS can be an indication of many things: hard water, healthy water, polluted water, you name it. The important thing to remember is high TDS may not mean low water quality and low TDS may not mean high water quality. It all depends on the type of TDS and volume of each forming the reading, as well as other contaminants in water that are not classified as dissolved solids and/or undetected by TDS meter