Novel methods for global water safety monitoring: comparative analysis of low-cost, field-ready E. coli assays Joe Brown*, Arjun Bir, Robert E.S. Bain *Corresponding author: School of Civil and Environmental Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332, USA. +1 404 385-4579. joe.brown@ce.gatech.edu Current microbiological water safety testing methods are not feasible in many settings because of laboratory, cost, and other constraints, particularly in low-income countries where water quality monitoring is most needed to protect public health. We evaluated two promising E. coli methods that may have potential in at-scale global water quality monitoring: a modified membrane filtration test followed by incubation on pre-prepared plates with dehydrated culture medium (CompactDryTM), and 10 ml and 100 ml presence-absence tests using the open-source Aquatest medium (AT). We compared results to membrane filtration followed by incubation on MI agar as the standard test. We tested 315 samples in triplicate of drinking water in Bangalore, India, where E. coli counts by the standard method ranged from non-detect in 100 ml samples to TNTC (>200). This data repository provides access to the raw data from this study.