Alkali is a corrosive substance that is often contrasted with acid. Water supplies with a pH above 7.0 have a lower acid content, which increases its alkalinity and tends to lead to a buildup of mineral scale. There are two key conditions for scale formation. The pH level must be neutral or above and there must be an energy transfer, cooling or heating, to act as a catalyst.
The normal range for pH in ground water lies between 6 and 8.5. When compared to other common liquids, vinegar measures 3 pH, beer measures between 4 and 5, and milk measures around 6.4 pH.
Drinking water with a pH level above 8.5 has more alkalinity and could indicate that the water is hard, which can cause aesthetic problems.
The effects of hard water
The seven key minerals that make up most rock formations in the United States are divided into two groups: cation and anions. Cations are positively charged minerals and include calcium, magnesium, sodium and potassium. Anions are negatively charged minerals and include carbonates, sulfates, and chlorides. Each type of rock has an equal number of cations and anions, and so does each water supply.
When we discuss “hard water” we are referring to a water supply with a concentration of the four hard minerals: calcium, magnesium, carbonate, and sulfate. These minerals are components of the hard rock formations that we call lime shale and gypsum.
Mineral deposits such as limescale create major problems for food service operations that use ice, coffee, espresso, steam and warewashing equipment. Mineral scale can clog tubing and small orifices, coat heating and cooling elements, and result in increased detergent usage. Scale also causes reduced energy transfer and efficiency loss, resulting in increased energy demands for cooling or heating, and increased operating costs. Increased operating costs include the need for deliming — an acid cleaning process that removes mineral scale. This process is harsh to the equipment surfaces and decreases equipment life. Learn more about scale.
Hard water with a high pH can be treated with a water softening system or a reverse osmosis system.
Learn about water softening.
Learn about reverse osmosis.