By Francis Fernandez Quoting from the AAQ Forum on India Water Portal TDS, Total Dissolved Solids content in water refers to the dissolved mineral content in water. The TDS content of any water is expressed in milligrams /litre (mg/l) or in parts per million (ppm). As the supply of water fails to meet demand more sources are being exploited leading to the subsequent proliferation of Reverse Osmosis systems, This has triggered a spate of questions about TDS on the forum. More specifically the majority of queries are linked to the effects of low TDS!! Concerns ranging from Health issues in the long run to the utility of a low TDS water source have been voiced on the AAQ forum. The forum maintained in collaboration with WES - Net India maintains a FAQ on TDS that strives to deal with the issues that are being raised. Going through the queries quoted above one can see a divergence in opinion related to low TDS and its effects. The need of the hour is to understand, more about the issue and form a consensus on the same. Readers are invited to let us know in the comments section about information, data sources or research related to low TDS and its effects. Let us know where you stand on the issue!