Supply system factors associated with microbiological drinking water safety in regional New South Wales, Australia, 2001–2007

Abstract

Aim: To determine factors associated with microbiological safety of public drinking water systems in regional New South Wales (NSW), Australia.Method: We analysed 107,000 end-user drinking water samples for an association between detection of Escherichia coli and drinking water system features, sample year and season using NSW Health Drinking Water Monitoring Program data, 2001-2007. We used negative binomial generalized estimating equations with adjustment for autocorrelation and clustering.Results: We detected E. coli in over 2% of samples from 40% (129/323) of systems. E. coli detection was significantly more common in earlier years and during summer ( p , 0.001).On multivariate analysis E. coli detection was significantly associated with smaller systems; watercourse sources; no disinfection or disinfection with ultraviolet only; and higher posttreatment mean turbidity (all p # 0.01). Detection was most strongly associated with lack of disinfection (incidence rate ratio 12.6, p , 0.001) and smaller supply systems (1% reduction in E. coli detection for each 1,000 person increase in supply population, p ¼ 0.004).Ultraviolet disinfection alone was the least effective disinfection method ( p , 0.001).Conclusion: Even in developed countries, drinking water systems without disinfection or serving small populations appear vulnerable to the effects of faecal contamination, which presents a risk of waterborne disease outbreaks.

Burden of Disease from Contaminated Drinking Water in Countries with High Access to Safely Managed Water: A Systematic Review

“…As an example, small water systems experience water quality and service delivery problems more often than larger systems due to the lack of economies of scale (Allaire et al, 2018; Cretikos et al, 2009; McFarlane and Harris, 2018). This is of particular concern when considering that small water systems frequently serve rural, low-income communities.…”

“…The high risks that some populations may face are subsumed when they are averaged in with the general population receiving high-quality water services. Among studies identified in this review, only Haass et al (Haass et al, 1996) As an example, small water systems experience water quality and service delivery problems more often than larger systems due to the lack of economies of scale (Allaire et al, 2018;Cretikos et al, 2009;McFarlane and Harris, 2018). This is of particular concern when considering that small water systems frequently serve rural, low-income communities.…”

Burden of disease from contaminated drinking water in countries with high access to safely managed water: A systematic review

“…Among studies identified in this review, only Haass et al 27 and Beaudeau et al 28 As an example, small water systems experience water quality and service delivery problems more often than larger systems due to the lack of economies of scale. [29][30][31] This is of particular concern when considering that small water systems frequently serve rural, low-income communities. Allaire et al found that violations of health-based drinking water standards in the US often occur in low-income rural areas.…”

Safe drinking water in regional NSW, Australia

“…A review of 107 000 samples collected from 2001 to 2007 found that systems with inadequate disinfection or serving small populations were more vulnerable to contamination. 5 Almost 40% of systems did not meet the target (i.e. no more than 2% of samples positive) for the faecal indicator Escherichia coli.…”