Systems for Rainwater Harvesting and Greywater Reuse at the Building Scale: A Modelling Approach

This building-scale modelling study examines how rainwater harvesting and greywater reuse can be combined within a single water system. Its practical relevance lies in the fact that it treats the two strategies as interconnected rather than separate, which reflects how many regenerative and self-sufficient buildings are designed in practice. By modeling system performance at the building scale, the study helps clarify how capture, reuse, and demand can be balanced to improve water efficiency. The source is particularly useful for architects, engineers, and planners because it suggests that integrated design can support better outcomes than isolated interventions. Building-scale modeling can reveal how much potable water demand can be displaced, how storage requirements interact with occupancy patterns, and how the two water streams can complement each other across different uses. That makes the article especially relevant for resilient design because it informs sizing and system configuration before construction begins. The study is also relevant to policy and project evaluation because model-based approaches are often used to assess feasibility and compare design options under different assumptions. Although the excerpt provided here does not include the full numerical results, it identifies the central methodological contribution: combining rainwater harvesting and greywater reuse in a modeling framework at the scale where most practical decisions are made. For regenerative living, that is significant because the building is often the key unit of water independence, and this source focuses directly on how to optimize that unit through integrated onsite water management.