Silica is a mineral naturally present in water from rock erosion. It's also used in industry. While generally safe, very high levels may affect kidney function in some people.

Silica, or silicon dioxide, is abundant in Earth's crust and enters water through natural erosion of rocks and soil. It's also used in various industries, including glass and semiconductor manufacturing. Water treatment plants don't typically remove silica, as it's considered harmless at normal levels. Measurement is usually done in parts per million (ppm) using colorimetric or spectrophotometric methods. While silica is essential for bone and connective tissue health, excessive intake may lead to kidney stones in susceptible individuals. However, such high levels are rare in drinking water.