Expanding access to water quality monitoring with the open-source WaterScope testing platform

Addressing the global water crisis, particularly in low-income communities, requires expanding access to affordable and reliable water quality testing. This paper introduces WaterScope, an open-source, validated platform for drinking water quality assessment. WaterScope modernizes testing with a cartridge/slider mechanism, machine learning-enhanced classification, and digital result reporting. Extensive validation confirms its accuracy in *E. coli* quantification, and its versatile design allows for expansion to other bacteria, colorimetric assays, and clinical sample analysis. The system's ease of use, portability, affordability, robustness, and digital nature promise to accelerate progress toward global water equality.

Alicja Dabrowska, George R. Lewis, Minaleshewa Atlabachew, Susannah J. Salter, Cassi Henderson, Chang Ji, Annike Ehlers, Julian Stirling, Sophie Mower, Lara Allen, Elizabeth Lay, Kara Stuart, Lisa Appavou, Richard Bowman, Tianheng Zhao, Nalin Patel, Alexander Patto, Mark A. Holmes, Jeremy J. Baumberg, Sammy Mahdi