Alkalinity, measured by carbonate levels, indicates water's acid-neutralizing capacity. It comes from rocks and soil. While not harmful, it affects water taste and treatment processes.

Alkalinity enters water as it flows over limestone, chalk, and other carbonate-rich rocks. It's typically measured in mg/L of calcium carbonate. While natural, high alkalinity can also result from industrial runoff. Water treatment plants monitor alkalinity closely, as it affects pH stability and chemical dosing. Alkaline water can form scale in pipes and appliances. Though not directly harmful, extremely high or low alkalinity may indicate other water quality issues that require attention.