Hard water is beneficial because it can provide much needed calcium and magnesium to humans, according to the Utah State University Extension Office. It has also been shown to have a correlation to a reduced risk of cardiovascular disease. Hard water is less likely to cause expensive corrosion of pipes, and it tends to taste better than soft water.
Hard water refers to water that has high levels of calcium and magnesium. The higher the level of minerals in the water, the harder the water is said to be. Water can be tested by a certified testing lab to find out the levels of minerals it contains.