Can I wash my solar panels with borewell water?

Using high-TDS hard water is highly discouraged. Over time, the calcium and magnesium in the water will dry and bake onto the hot glass, creating a hazy white 'scale'. This scale blocks sunlight and is notoriously difficult to remove, often requiring specialized chemicals that can damage the panel's anti-reflective coating. If you must use borewell water, make sure to vigorously squeegee the panels completely dry immediately after washing.