What does a pH level below 6.6 in treated water typically indicate?

A pH level below 6.6 in treated water typically indicates that the water is becoming acidic, which can lead to corrosive properties. When water has a low pH, it means there is a higher concentration of hydrogen ions, making it more aggressive in dissolving materials it comes into contact with, such as metal pipes and fixtures. This corrosiveness can result in leaching of harmful metals into the drinking water supply, potentially posing health risks.

Maintaining a proper pH balance is crucial in water treatment because water that is too acidic can cause significant problems in distribution systems and affect the quality of the water. The ideal pH for drinking water is generally around 7.0 to 8.5, so a level below 6.6 indicates a need for adjustments to ensure safety and prevent corrosion.

In contrast, high alkalinity refers to the capacity of water to resist changes in pH, and a free chlorine residual greater than 1.0 mg/L may indicate effective disinfection but does not directly correlate with acidity. Extremely high total solids content may affect the turbidity and quality of water but typically does not directly relate to the pH level being low.