The hardness of drinking water should be?
ANSWER: (C) 1-3REF: Park 20th ed p. 636Drinking water should be moderately hard. Softening of drinking water Is recommended when the hardness exceeds 3 mEq/LClassificationLevel of hardness ( mEq/L)Soft water< 1 ( < 50 mg/l)Moderately hard1-3 ( 50-150 mg/l )Hard water3-6 (150-300 mg/l)Very hard water> 6 ( > 300 mg/l)
>3
<1
3-Jan
>6
Water