Hard water and soft water are defining depending on water contaminants with some metals ions such as calcium, magnesium. Hard water is not good for all position; same way soft water also not suitable for all applications.
Generally hard water contains greater quantity of calcium and magnesium ions. On the other hand soft water contains little amount or no ions of some metals such as calcium, magnesium. We get soft water naturally such as rain water or conditioning the hard water.
Water for drinking purpose
Hard water is good for health than soft water. In health point of view hard water effects are neutral; some cases are beneficial because it is rich in minerals. Moreover it decreases the solubility of potentially poisonous metal ions as like copper and lead. On the other hand soft water rich in sodium ions, this is not safe to drink. It is health risk such as diabetes or high blood pressure. A study shows that less heart disease in hard water areas than in soft water areas.
Water for domestic cleaning
For domestic cleaning soft water is essential. Hard water is not suitable for this purpose because in hot water heater, steam iron, kettles, coffee makers etc it forms limescale. This water also creates spots on dishes and glassware. Moreover extra soap or detergents are consumed in this case. In addition hard water leaves iron or soap deposits in bathtubs, sinks and basins. On the other hand soft water save soap or detergents and all other hard water effects are not found in case of domestic cleaning.
When people are bathing with soap in hard water, a sticky film formed on the skin. Soil, dirt and bacteria can be trapped in pores beneath the soap scum; this is the possible skin infection.
Water for plumbing system
Domestic or industrial plumbing system is affected by hard water. It buildup limescale in shower head, taps, inner side of pipe, hot water tanks, washing machines, boilers, cooling tower and other industrial equipment. It reduces the life of plumbing system; even clog it. Hence increase plumbing system repairing cost. On the other hand these effects are not found in case of soft water.
Water for industry
In industrial purpose the uses of soft water is significant. Soft water is used for heat transfer, cooling tower, boiler, manufacture of beverages, sugar syrup, gelatin, juice etc in many industries. In contrast hard water is not suitable for industry; it buildup limescale in boiler, cooling tower, hot water tank etc. as a result decrease the life of tank or boiler and need more energy. Water hardness significantly effects on textile dyeing, washing and finishing section.