Rainwater harvesting (RWH) is increasingly seen as a significant water source and a strategy for improving water supply in arid and semi-arid regions. However, RWH facilities are regularly threatened by various factors influencing its effectiveness and making them unsustainable. This paper aims to quantify the factors influencing RWH effectiveness in arid and semi-arid regions of Sudan. The factors categorized into socioeconomic variables indicated by household family size, household income, and household animals. Environmental variables include rainfall amount, soil type, and water availability at the home. The institutional variables are indicated by government support, nongovernmental (NGO) support, and community involvement. Five small dams of water harvesting located in different five states in Sudan were selected. Several 150 households, 30 households per dam were randomly assigned to respond to a questionnaire designed to collect data on factors influencing RWH facilities. Preliminarily, Pearson’s Chi-square test was used to determine the variables for the logistic model. Multiple logistic regression was used to identify the most influential factors on the effectiveness of water harvesting dams. The results show that 40% of the RWH facilities were effective. A significant (p-value < 0.05) relationship exists between socioeconomic, institutional and environmental factors and the effectiveness of the RWH facilities. The results revealed that household animals, government support, community participation, rainfall, and soil types significantly (p-value < 0.01) influence the RWH facilities to be effective. The results are of great importance for future effective and inclusive water harvesting initiatives in arid and semi-arid regions