Sustainable innovations are observed as a major way by which the ill-effects of the built environment can be avoided or offset. The adoption of innovations are critical to the society, as they pave the way for further incremental or radical innovations, depending on the feedback from their users. In this process, the attributes of an innovation play an important role in its adoption. The objective of this study was to determine whether observability, one of many attributes of innovations identified in the literature as affecting their adoption, plays a critical role in the adoption of sustainable innovations, specifically Rainwater Harvesting Technologies and Strategies (RwHTS). Further, the study aimed to determine whether the use of Building Information Modeling (BIM) resulted in frequent adoption RwHTS. Last but not least, the study also sought to understand how designers used BIM to enhance the acceptance of RwHTS in capital projects. The stakeholders identified for this study were architectural firms that are geographically located in the southeastern states of the United States, and the study was conducted from their perspective. This study was segregated into two major phases. The first phase involved a survey of 2,200 designers/architects located in seven southeastern states, including Georgia, North Carolina, South Carolina, Florida, Virginia, Maryland, and District of Columbia. The survey questions targeted experiences associated with the implementation of RwHTS and the use of BIM for designing and constructing facilities over the last decade by the architectural firms. Based on the responses received, six firms were purposively selected for Phase II, which involved a case study approach that included meeting with the designers, conducting interviews, understanding general firm policies for capital projects, identifying factors that result in the adoption of RwHTS, and developing a process-based profile undertaken by the firm to understand how key decisions were made. By the end of this phase the researcher identified the factors that result in the adoption of RwHTS. In addition, the researcher also found that observability did not emerge as an attribute that played a critical role in the adoption of RwHTS, in comparison to the other attributes. The study also found that the current use of BIM did not result in the frequent adoption of RwHTS. Finally, the study was able to produce a generalized process map that depicted the steps undertaken during the design process for the adoption of RwHTS in capital projects. This study encompassed the basic principles of sustainability in the built environment, adoption of innovation, and Building Information Modeling use within the design industry.