Social & Preventive Medicine Guideline value for drinking water is: September 2007 A 1 coliforms per 100 ml B 10 coliforms per 1000 ml C Zero coliforms per 100 ml D 100 coliforms in 10,000 ml 💡 Explanation Guideline value for drinking water is: September 2007 ✓ Correct Answer: C. Zero coliforms per 100 ml