What concentration of iron is recommended by the secondary standard not to exceed?

The recommended concentration of iron not to exceed, according to secondary standards, is 0.30 mg/L. This guideline is set based on aesthetic considerations, as elevated levels of iron in drinking water can lead to undesirable tastes, staining of laundry, and discoloration of plumbing fixtures. While higher concentrations might not pose significant health risks, the secondary standard focuses on maintaining acceptable quality for public consumption.

Secondary standards are developed to address consumer complaints and maintain the quality of water rather than to protect against health risks. The established limit of 0.30 mg/L effectively balances the need for clean drinking water while minimizing potential negative impacts on water use and quality in everyday applications.