A positive Langlier index reading indicates that the water is what?

A positive Langlier index reading indicates that the water is scaling, meaning it has the potential to precipitate calcium carbonate (CaCO3) as it is supersaturated with respect to this mineral. This occurs when the water's pH, temperature, and total dissolved solids levels create an environment conducive to the formation of calcium carbonate deposits. Scaling water can lead to problems in distribution systems and water-using appliances, as it may cause scale buildup inside pipes, boilers, and other equipment, resulting in reduced efficiency and increased maintenance costs.

Understanding the Langlier index is important for water operators because it helps in managing water quality to prevent such issues. When the index is positive, measures may need to be taken to adjust water chemistry or treatment processes to mitigate scaling and maintain the system's integrity.