WHY DELHI VARIES
Delhi does not behave like one single water zone.
Water hardness can shift by locality, source, building type, and storage system. Some homes see mostly treated municipal water. Others depend more on groundwater or tanker backup. Storage tanks and old plumbing can change the actual water that reaches the appliance.
That is why two Delhi flats can have different descale rhythms even when they share the same broad city label. A city-level TDS number is a baseline, not a building-level certificate.
