Drinking water quality in regional Hunter New England, New South Wales, Australia, 2001-2015

ABSTRACT The objective of this study was to evaluate the effectiveness of drinking water quality verification monitoring as a means of improving preventive measures on drinking water quality management in regional New South Wales (NSW), Australia. Water sampling and E. coli detection data were obtained from the NSW Drinking Water Database. Statistical analysis was performed using Incidence Rate Ratios to compare the relationship between the proportion of samples collected to the tests allocated based on population served (sampling adequacy), E. coli detection and the relationship between sampling adequacy and E. coli detections over time. Sampling adequacy and E. coli detections significantly improved during the study period. Sampling adequacy was significantly lower in smaller populations (IRR = 0.83, p = 0.036). E. coli detections were significantly increased in smaller communities (IRR = 4.3, p = 0.01) and in summer (IRR = 2.7, p = < 0.001). There was a strong inverse correlation between improved sampling adequacy and decreased E. coli detections (Spearman’s rho = −0.821; p < 0.0001). This research has highlighted the value of continued assistance to water utilities in the implementation of drinking water management systems to improve drinking water safety.