How the water quality is, it can't be judged simply from a project index. Evian mineral water is about 300, and Wahaha pure water is less than 5. However, it cannot be concluded that Wahaha is better than Evian.
The lower the TDS value, the purer the water. The higher the TDS, the higher the dissolved solids in water, but this does not mean that the water quality is not good. Because soluble solids may be pollutants or beneficial trace elements.
In a word, it is one-sided to judge water quality with a single TDS value.