Certified Pool Operator Practice Test

Water with a pH of less than 7.0 is considered acidic. This is because a pH of 7.0 is considered neutral, so any value below that is considered to be more acidic. Option B (Alkaline) is incorrect because water with a pH less than 7.0 is not considered to be alkaline. Option C (Neutral) is incorrect because neutral pH is 7.0, higher than the pH described in the question. Option D (Basic) is incorrect because basic substances have a pH above 7.0. It is important to remember that pH is measured on a scale of 0-14, with 0 being most acidic and 14 being most basic. Therefore, a pH of less than 7.0 indicates an acidic substance.