At what concentration does iron cause "red water," leading to customer complaints?

Iron concentrations can lead to the formation of "red water," which is a common problem in water distribution systems that leads to customer complaints about the water's appearance and taste. Generally, red or brown discoloration due to iron in water is observed when concentrations exceed approximately 0.3 mg/L. At this level, the iron may become solubilized, and when it oxidizes, it forms iron oxides, which impart a reddish or brown hue to the water.

Understanding this threshold is important for water operators to manage and control iron levels in drinking water effectively, as exceeding this concentration can result in significant dissatisfaction among consumers due to the visual quality of the water they receive. Hence, maintaining iron concentrations below this level is crucial for providing high-quality water and ensuring customer satisfaction.