Improving drinking water disinfection in a rural community-managed aqueduct of Costa Rica

ABSTRACT Disinfection is fundamental to ensure safe drinking water. Although multiple disinfection methods are available, chlorination remains the most widely used due to its residual protection, low cost, and adaptability to both urban and rural water systems. However, chlorination in rural or small-scale aqueducts is often conducted empirically, using general or trial-and-error protocols that overlook site-specific characteristics such as baseline water quality, flow variability, and disinfectant properties. This study presents the first assessment of a disinfection system in a rural Community-Based Water Management Organization (CBWMO) in Poás, Costa Rica. In the present work, the water system was evaluated and determined chlorine requirements. Most physicochemical parameters complied with national and international drinking water guidelines. However, raw water sources were classified as fair-to-marginal quality and as high to very high risk for human consumption, while operational and structural deficiencies were identified in the disinfection systems. To address these issues, a critical control points checklist, and a chlorinator calibration model based on chlorine demand curves and water flow were developed. These results were integrated into a standard operating procedure to improve CBMWO operations. This framework can be transferred to other rural and small-scale aqueducts lacking technical information on disinfection performance.