Water quality in rainwater harvesting systems: influence of the collection material and pretreatment in Coata, Peru

Laqui W.; Mamani J.; Alfaro-Alejo R.; Sardón-Ari D.; Sardón-Ari Z. · Sustainable Water Resources Management (2026) · DOI: 10.1007/s40899-026-01394-w

Resumen

Water scarcity and contamination of groundwater sources pose a significant challenge to rural communities in Coata, Puno. The purpose of this study was to analyze how the type of roofing material and the effectiveness of the first flush diversion system influence the quality of water collected in rainwater harvesting systems, compared to the maximum permissible limits according to Peruvian regulations. Three rainwater harvesting systems with different roofing materials (Aluzinc steel sheet and zinc sheet) were installed, and samples were taken during April 2025 and analyzed according to standard methods for physicochemical and microbiological parameters. The results indicated that the rainwater showed low mineralization, complying with the maximum permissible limits. However, the zinc sheet increased the initial chemical load, releasing zinc, iron, and aluminum above the maximum permissible limits in the first runoff. The system first flush diversion reduced these metals by more than 80%, ensuring the chemical quality of the stored water. Despite this, persistent microbiological contamination by total and thermotolerant coliforms was detected, requiring additional disinfection treatment. In summary, rainwater harvesting appears to be a viable option to supplement the domestic water supply in Coata; however, comprehensive management of the initial runoff and subsequent disinfection are necessary to guarantee the potability and sanitary safety of the resource. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2026.

Instituciones: Universidad Nacional del Altiplano