Water hardness is the traditional measure of the capacity of water to react with soap and describes the ability of water to bind soap to form lather (ang pagbukal sang habon), a chemical reaction detrimental to the washing process. Hardness has little significance in terms of hydro-chemical studies, but it is an important parameter for the household water used. Technically water hardness is significant because its corrosive effect on pipes which carries our water.

Mana-ay, E. (2018, October 29). The hard and soft water story. The Daily Guardian, p. 4.