<prompt> Hardness of drinking water should be?313-Jan6  <response>: Drinking water should be moderately hard.Softening of water is recommended if hardness ecxeeds 3mEql. Soft water- 1 mEql Moderately hard- 1-3 mEql Hard water- 3-6mEql Very hard water- 6mEql Parks textbook of preventive and social medicine.K Park. Edition 23.Pg no: 727 