Planning Rainwater Harvesting in Social Housing: A Decision-Support Framework for Selecting Implementation Scales

Source abstract

Planning rainwater harvesting (RWH) systems for social housing requires decisions that extend beyond technical design, particularly regarding implementation scale. Although previous studies have extensively addressed storage sizing, water savings, and technical performance, comparatively less attention has been given to how implementation scale affects governance, maintenance, social outcomes, and long-term sustainability. This study compares two real-world RWH applications in Brazilian social housing contexts, representing household- and community-scale implementation. The systems were assessed across technical, operational, governance, and social dimensions. The comparison shows that household-scale implementation is associated with greater operational autonomy, simpler maintenance, and easier replication, whereas community-scale implementation can extend social benefits and collective resource use but requires stronger governance and coordinated management. Based on the case-study evidence and supported by the literature, a planning-oriented decision-support framework is proposed to guide implementation-scale selection according to local conditions, management capacity, and project objectives. The findings highlight implementation scale as a strategic planning variable for decentralized urban water infrastructure in social housing.