Water Safety Plans: Risk assessment for consumers in Drinking Water Supply Systems

Abstract

Consumers are the last stage in Drinking Water Supply Systems (DWSS) and they are characterized by their vulnerability to hazards due to the proximity of consumption point. The aim of this study is to carry out the risk assessment on water consumer in DWSS in Cali, which is supplied by Cauca River and framed in the philosophy of Water Safety Plans (WSP). Tools such as the matrix of hazards or hazardous events, monitoring water quality, conducting household surveys, and a semi-quantitative matrix for risk estimation were used. The results showed consumers’ low perception on health risk and a lack of knowledge on their responsibility for protecting drinking water quality, which can lead to an inappropriate behavior affecting the integrity of the internal distribution system. Although most analyzed variables met national regulations, some monitored  points  into  buildings  showed  low  values  of  residual  chlorine  and  high  values  of  heterotrophic  plate  count  bacteria, suggesting potential risks related to the presence of biofilms. The participation and commitment to fall involved stakeholder actors are key strategies to avoid misbehaviors, and thus, reduce risks. Besides, the promotion of educational campaigns as indicated by national regulations must be performed.