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For pure water the hardness is very low because in it low dissolved ions. Water with no dissolved solids usually has flat taste, whereas water with more than 500mg/l tds has a disagreeably taste. In case of industrial effluent water in which many dissolved ions are their the hardness is very high and it will show many soluble matter in it. The hard water retards the cleaning action of soaps and detergents causing an expense in the form of extra work and cleaning agents. Furthermore, if the hard water is heated it deposits a hard scale on heating coils, cooking utensils, and other equipment with a consequent waste of fuel. The scale formed by the hard water coats the inside of distribution system piping, which can eventually cause significant reduction in its water carrying capacity.