What is the Secondary MCL for pH?

The Secondary Maximum Contaminant Level (MCL) for pH in drinking water is established to help manage aesthetic qualities such as taste, color, and corrosion of plumbing systems. The range of 6.5 to 8.5 is significant as it encompasses the pH levels that are typically suitable for drinking water and helps prevent problems associated with water that is too acidic or too basic.

Water with a pH lower than 6.5 can lead to increased corrosion of plumbing, which can result in leaching of metals into the water supply, whereas water with a pH higher than 8.5 may have a soapy taste and can cause scaling in plumbing systems. Thus, the chosen range is designed to protect public health and maintain water quality.

Other options are incorrect because they do not fall within the established range of 6.5 to 8.5, which is the range of values recommended to prevent aesthetic and corrosion-related problems in drinking water systems.