Exam EDGE-Expert Topic 1 Question 64 Discussion

In the EDGE water assessment, rainwater harvesting contributes to savings only when the collected rainwater is used to directly reduce the building's demand for potable or municipal water. The curriculum explains that qualifying water savings must come from substituting potable water in recognized end uses such as toilet flushing, irrigation, and cooling tower make-up water where applicable. When rainwater is used as make-up water for cooling towers, it displaces treated potable water that would otherwise be required for heat rejection systems, and this reduction is captured in the EDGE software water calculations.
By contrast, options such as groundwater recharge or simply redirecting rainwater to drains or nearby water bodies do not reduce the building's potable water consumption. These actions may be beneficial for stormwater management, flood control, or environmental protection, but they do not represent a direct offset of the building's indoor or process water demand in the way EDGE quantifies water savings for certification.
Therefore, the valid use that qualifies for EDGE water savings in this question is using collected rainwater for cooling towers.