‘e-Taps’ monitor flow at rural water points in sub-Saharan Africa and enhance revenue collection using pre-paid tags. Real-time, high temporal resolution e-Tap usage data is available to service providers. In this paper, robustness of the e-Tap is evaluated in the laboratory regarding (1) accuracy of the flow meter and (2) the flow rate reduction caused by addition of a y-strainer and debris build-up. An average relative error of +3.63% across varying flow rates is found. A general calibration will bring 95.45% of measurements within ±4.54% error range. In the y-strainer, smaller gauze sizes, smaller debris sizes, and higher debris loads cause greater flow rate reductions. The maximum reduction observed was only approximately 68% of the baseline flow rate. These physical findings can be integrated into software solutions to management problems.


  • An evaluation of a novel technology that is currently scaling across rural water supply systems in sub-Saharan Africa. This level of rigour is new for these technologies, and will direct development here and with other similar technologies.

  • The findings provide solutions to inaccuracies, and demonstrates that refinements to the technology can be made remotely, a which is novel. This has enormous potential benefits to the sustainability of water supply in this context.

  • Results provide a basis for predictive maintenance/cleaning.

  • The research here will act as a reference for other researchers working on flow rate reductions from debris build-up, or on flow meter accuracy for decentralised, small-scale, rural technologies.

  • The closest work focuses on lower-accuracy/resolution handpump sensors. The direct measurement evaluated here has three times greater accuracy.

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Supplementary data