evaluation that aims to measure the causal impact of a large-scale rural water supply and services program (PROSASR) in Nicaragua. The overall objective of the evaluation is to assess the causal impact of the provision of technical assistance packages on improvements in the functionality and durability of water systems in rural Nicaraguan communities. Prior to the implementation of the intervention, baseline data were gathered to assess the current levels of functionality and durability of water supply and sanitation (WSS) services, organizational structure and preparedness of WSS system providers, and rural communities and households served by rural water systems. Baseline results suggest that randomized program assignment at the community level resulted in balanced characteristics between treatment and control groups. In a secondary exploratory analysis, community, household, and system indicators were used to identify key determinants of the sustainability of rural water systems. These results will help determine the roadmap for constructing a consistent follow-up survey (2018) to conclude the evaluation and obtain practical policy and program recommendations to improve the program's effectiveness.