This study examines a broad array of theory-based factors derived from diffusion research that affect the current and intended use of solar water disinfection (SODIS), a simple, low-cost technology for treating drinking water at the household level. The perceived attributes of an innovation, the nature of the social system in which it is diffused, the extent of change agents' promotional efforts in diffusing it, and the nature of the communication channels used were operationalized by 16 variables. The aim of the study is to determine the influence of each factor and its predictive power. Eight areas in Bolivia were visited, and 644 families were interviewed on the basis of a structured questionnaire. Simultaneous multiple regression analysis showed that 9 of the 16 factors derived from diffusion research contributed significantly to predicting the current use of SODIS. The implications of the findings for customizing future SODIS diffusion activities are outlined.