Which of the following pH levels is considered acidic for drinking water?

A pH level below 6.5 is indeed considered acidic for drinking water. In terms of the pH scale, which ranges from 0 to 14, any reading below 7 is categorized as acidic, while a reading of 7 is neutral, and readings above 7 are alkaline or basic.

Drinking water with a pH below 6.5 can lead to corrosion of pipes and fixtures, potentially leaching metals like lead and copper into the water supply, which poses health risks. Therefore, it is crucial for water quality management to monitor and maintain pH levels within a safe and neutral range, ideally between 6.5 and 8.5, to ensure the safety and palatability of drinking water.

Options indicating a neutral pH, such as 7.0 or ranges that include neutral to alkaline levels (like between 6.5 and 8.5 and above 8.5), do not fall into the acidic category. Thus, the focus remains on the importance of maintaining pH above 6.5 to avoid the risks associated with acidic water.