Sanitary Inspection (SI) has long been used as a low-cost, on-site risk assessment tool for water supply systems. The tool consists of a set of questions/checklist of relevant and observable conditions, design features, and potential sources of contamination that may affect water safety. Sanitary inspection forms developed by the World Health Organization (WHO) have been widely used, particularly in rural settings in low- and middle-income countries, as part of routine water safety monitoring and management practices. WHO is currently in the process of reviewing and updating the sanitary inspection forms it published in 1997, and piloting their use in multiple settings to maximize validity and ease of use.
The Water Institute (WI) is working with WHO and stakeholders to review and provide input on draft updated sanitary inspection forms. As part of this work, the WI team is reviewing thousands of sanitary inspection observations collected by our partners from small drinking water systems across multiple rural settings in low- and middle-income countries. These observations are linked to microbial water quality data collected at the time of the sanitary surveys. In addition, the WI team have linked these observations with rainfall data and other relevant datasets. We are analyzing these merged datasets to characterize and validate the association of various risk factors with vulnerability to microbial contamination during rainy vs dry periods for different water system types.
Sanitary inspection data are not surrogates for microbial water quality data, and their value is not limited to their association with the occurrence of fecal indicator bacteria in water samples. However, across thousands of observations and multiple settings, and after controlling for relevant covariates such as rainfall and other factors, understanding the ways in which risk factors predict vulnerability to contamination, both individually and collectively, can help validate and refine the ways in which sanitary inspections are designed, implemented, and interpreted.
As part of this work, the WI team is identifying which water conditions are the strongest predictors of contamination under different circumstances, which attributes can be combined with no loss in predictive power vs which should be assessed as distinct indicators, and which interactions may be important in understanding microbial contamination. In addition to addressing water safety, we are also performing preliminary analyses to better understand which existing and potential sanitary inspection items may also be associated with water source functionality, particularly after controlling for estimated ground water depth from global datasets. Finally, we are investigating the potential of these data and analyses to highlight which systems may be most vulnerable to contamination and/or nonfunctionality as a result of extreme weather events and/or climate change.
Anthropogenic climate change is already causing increased intensity of droughts and floods around the world, and worsening water source contamination and water scarcity. Our work will help contribute to the body of knowledge available to WHO, policymakers, and service providers to identify and address potential vulnerabilities in water systems to more effectively and sustainably ensure safe water for all.