Increasing access to water quality tests in low-income communities is a crucial strategy toward achieving global water equality. Recent studies in the Water Sanitation and Hygiene (WASH) sector underscore the importance of addressing practical concerns in water testing, such as robustness and results communication. In response, we present the WaterScope testing kit; an open-source, validated platform for drinking water quality assessment. It modernises the testing process with the inclusion of a unique cartridge/slider mechanism, machine-learning-enhanced classification and full digitalisation of results. WaterScope’s equivalency to conventional methods for quantifying E. coli is established through extensive validation experiments in both laboratory and field environments. This versatile platform provides potential to expand its applications to test other bacteria, perform colorimetric assays, and analyse clinical samples such as blood/urine samples. We anticipate that the system’s ease-of-use, portability, affordability, robustness, and digital nature will accelerate progress toward global water equality.