Hard water is water that has high mineral content. Hard drinking water is generally not harmful to one’s health, but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that handles water. In domestic settings, hard water is often indicated by a lack  of suds formation when soap is agitated in water, and by the formation of limescale in kettles and water heaters. Wherever water hardness is a concern, water softening is commonly used to reduce hard water’s adverse effects.

Alkalinity is the name given to the quantitative capacity of water to neutralize an acid. Measuring alkalinity is important in determining a stream’s ability to neutralize acidic pollution from rainfall or wastewater. It is one of the best measures of the sensitivity of the stream to acid inputs. Alkalinity measurement is important in the control of water and wastewater treatment.

Hydrogen Ion Concentration and pH. pH is a measure of how acidic/basic water is. The range goes from 0 – 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base. pH is really a measure of the relative amount of free hydrogen and hydroxyl ions in the water. Water that has more free hydrogen ions is acidic, whereas water that has more free hydroxyl ions is basic. Since pH can be affected by chemicals in the water, pH is an important indicator of water that is changing chemically. Water with a pH of five is ten times more acidic than water having a pH of six.

Nitrates and nitrites are nitrogen-oxygen chemical units which combine with various organic and inorganic compounds. Due to its high solubility in water, nitrate is one of the most common contaminants in rural and suburban areas. In ground water, nitrate originates primarily from fertilizers, septic systems, and manure storage or spreading operations. Nitrate may also occur naturally due to the dissolution of nitrate bearing rock within the aquifer. With surface supplies, contamination can originate from indiscriminate surface water runoff (non-point sources) or identifiable sources of contamination such as industrial or municipal discharges (point sources).

Iron, even in small quantities, can be one of the most troublesome elements found in water. Iron and manganese deposits will build up in pipelines, pressure tanks, water heaters and water softeners. This reduces the available quantity and pressure of the water supply. Iron and manganese accumulations become an economic problem when water supply or water softening equipment must be replaced. There also are associated increases in energy costs from pumping water through constricted pipes or heating water with heating rods coated with iron or manganese mineral deposits.