The international community has been busy establishing new indicators for the Sustainable Development Goals (SDG) #6:
· Percentage of the population using safely managed drinking water services
· Percentage of population using safely managed sanitation services, including a handwashing facility with soap and water
To build these indicators, countries need to indeed go beyond self-reported questions. The new definition of safely managed drinking water requires conducting at least a 100mL presence/absence water quality test of the source from which the household gets its drinking water (as well as self-reported information that the source is an improved type, on premises, and available when needed).
More information on this and the World Bank's role can be found at this link, using the case study of Ecuador to show how the new baselines are being collected: