TDS (Total Dissolved Solids)

TDS (Total Dissolved Solids) measures the total milligrams of minerals dissolved per liter of water — the mass a water carries from its source rock. It is the primary way premium and fine waters are classified. The Fine Water Society scale runs Super Low (<50 mg/L) → Low (50–250) → Medium (250–800) → High (800–1500) → Very High (>1500). The US FDA requires ≥250 mg/L for the "mineral water" label, and crucially, those minerals must be present at the source — they cannot be added post-extraction. Common reference points: Acqua Panna 188 mg/L, Evian 357 mg/L, Perrier 475 mg/L, Topo Chico ~950 mg/L, San Pellegrino 1,109 mg/L, Gerolsteiner 2,527 mg/L. Higher TDS yields a more pronounced mineral mouthfeel; lower TDS reads as soft, clean, and 'invisible.'