Water Efficiency, Consumption and Management in Environmental Performance Assessment Methods for Existing Buildings in Use

Abstract

One of the major motivations behind the effort for the transition from linear models to circular ones in the building sector is related to the need for the minimization of resources depletion. Water holds a prominent position among those resources. The building sector is responsible for appreciable water consumption and, hence, represents an important field for improvements. While in the case of new buildings several options are available for the relevant systems and strategies, when existing buildings are considered, the limitations are multiplied in the context of decisions already made and materialized. However, the existing building stock is a massive contributor to the total impact of the built environment and must be considered as well. In this work, three buildings’ environmental performance assessment methods (BREEAM, DGNB, LEED) and, specifically, their versions for existing buildings in use (residential and non-residential), are examined regarding the way water-related parameters are implemented in the evaluation that they perform. The factors reviewed are those associated with water regarded as a resource (water consumption, (re-)use of rainwater, management issues etc.) and not the ones referring to flood risks and to energy demand (hot water). The analysis’ main focus lies in the criteria used by each method, the main strategies highlighted as advantageous, and issues related to the integration of those evaluation axes into each system. Initially, main features of the three methods are presented (assessment structure, scoring process, etc.). Among others, differences and similarities in the adopted approaches (three evaluation methods, various building uses) are highlighted and discussed.