Water pH

Just as water hardness is a measure of the amount of minerals, pH is a measure of the acidity or alkalinity of water. The pH scale (Figure 7.6) runs from 0 to 14. At pH 7, water is neutral—neither acidic nor alkaline (basic). If acid is present, pH falls below 7. If base or alkali is present, it rises above 7. Water supplies rarely have a neutral pH. Areas of North America plagued by acid rain— Canada and the United States along the Atlantic coast, for example—typically have water with a low pH.