As per BIS 10500:2012, the ACCEPTABLE limit of total hardness (as CaCO3) in drinking water is:

• A 75 mg/L
• B 200 mg/L ✓
• C 500 mg/L
• D 600 mg/L

Explanation

BIS 10500 sets the acceptable limit of total hardness at 200 mg/L and the permissible limit in the absence of an alternate source at 600 mg/L. Water above 200 mg/L causes encrustation in pipes and more soap consumption, while very soft water below 75 mg/L may corrode pipes and has been linked to cardiovascular disease in some studies. Option D (600) is the permissible ceiling, which kills that distractor.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.