The pH of ordinary water is usually around 7, which is considered neutral. The pH scale measures the acidity or basicity of a solution on a scale from 0 to 14, with 0 being the most acidic, 14 being the most basic, and 7 being neutral. Pure water has a pH of 7, but the pH of ordinary water may vary slightly due to the presence of dissolved substances, such as minerals and pollutants.