Surveillance of the chemical and microbial quality of drinking water for safe water supply in an urban area

To ascertain the quality of drinking water, surveillance of drinking water quality was conducted in Bhopal. The water supply to water treatment plants (WTPs) is from Kolar dam and Upper Lake. There was no significant change in water quality at the Kolar WTP on a day-to-day basis except in summer, when the manganese content of raw water was 0.3–0.4 mg/L, which was removed during treatment. The treated water quality from Birla Mandir WTP was within desirable limits during all the seasons. Filtered water from Idgah WTP showed significant coliform counts, indicating malfunctioning of filter beds. However, after chlorination coliforms were absent. For Phulphukta WTP, residual chlorine at the sump was 0.8–2.0 mg/L; therefore finished water was free from bacterial contamination. The finished water quality of all the WTPs met Central Public Health and Environmental Engineering Organisation guidelines. Although the sump water was free from bacterial contamination, it was contaminated with coliforms at the consumer end, which may be attributed to improper maintenance of service reservoirs and contamination en route. The proper maintenance of the distribution network, awareness of hygienic and sanitary conditions around public taps and proper storage of water are prerequisites for maintaining a safe water supply in the city.