Rapid drinking water safety estimation in cities: Piloting a globally scalable method in Cochabamba, Bolivia

Systematically collected and comparable data on drinking water safety at city-scale is currently unavailable, despite the stated importance of water safety monitoring at scale under the United Nations Sustainable Development Goals (SDGs). We developed a rapid drinking water quality assessment methodology intended to be replicable across all cities and useful for monitoring towards achieving SDG 6 (Clean Water and Sanitation). We collected drinking water samples at the point-of-consumption for basic microbial, physical and chemical water quality analysis and conducted household surveys on drinking water, sanitation, and hygiene access from 80 households in the city of Cochabamba over 1 week. We categorized the household's water service level according to the SDG 6 framework. We estimated an average time requirement of 6.4 person-hours and a consumable cost of US $51 per household (n = 80). In this cross-sectional study, 71% of drinking water samples met World Health Organization (WHO) microbiological safety criteria, 96% met WHO chemical quality criteria, and all met WHO aesthetic quality criteria. However, only 18% of the households were categorized as having safely managed drinking water services. None met the criteria for having safely managed sanitation services; nonetheless, 81% had basic sanitation services and 78% had basic hygiene facilities. This method can generate basic water safety data for a city at a relatively low cost in terms of person-time and materials, yielding useful information for inter-city analyses. Because 29% of samples did not meet microbiological safety criteria, 22% of the households did not have access to handwashing facilities and none had safe sanitation services, we concluded that Cochabamba did not meet normative SDG 6 targets when surveyed. Our study further suggests that water quality at point-of-use more accurately characterizes drinking water safety than infrastructure type. [Display omitted] •Robust data on drinking water safety is currently not available for many cities.•This is a standard and scalable methodology where data is not readily available.•Access to infrastructure does not mean access to safe water.•Current drinking water safety levels in Cochabamba do not meet UN SDG 6.•This method yields credible and comparable urban drinking water safety data.