Frequent cases of gastroenteritis, resulting in several fatalities within remote communities in the Yasawa Islands, Fiji, prompted an urgent drinking water quality and supply assessment. This project initially investigated the quality of drinking water from multiple sources in communities on Naviti Island. Escherichia coli was detected in all sampled sources, including wells, springs, and rainwater tanks (above ground). E. coli most probable number counts were higher in well and spring water (typically >100 organisms per 100 mL) than rain tanks (ranging between 13.6 and >100). Assessment of potential water treatment alternatives, incorporating community input, determined that disinfection of rain tanks through chlorination was the most feasible and community acceptable option to address the contamination. A model was then developed to assess: (1) the likelihood that a typical household rainwater tank could adequately supply water throughout the wet and dry seasons and (2) the likely free chlorine residual that would result from a program of periodic dosing with 12.5% sodium hypochlorite. In a pilot trial in Mua-Ira village, chlorination of rainwater tanks proved successful in removing E. coli and community rollout was initiated. Periodic chlorination paired with tank and gutter maintenance were recommended to community and a local partner organization, and a training package was developed to assist this. The project holds potential to minimize pathogenic bacterial contamination in the studied drinking water sources and serve as a model to address water contamination through simple, low-cost, community-accepted solutions in the wider region.