Water Footprint of the Life Cycle of Buildings: Case Study in Andalusia, Spain

The building sector is one of the major consumers of water resources, according to the United Nations Environmental Program, buildings and their associated industry consume 30% of the fresh water available worldwide. Optimizing this resource usage is a key factor and makes it necessary to analyze it with environmental and economic indicators, so that the magnitude of the impact can be qualified and quantified, and covering all the building life cycle. The analysis includes the first stage, the project conception, follows with the assessment of raw materials and its manufacture, continues with the use and maintenance, and finalizes with the demolition of the building. The water consumed in all those processes or Virtual Water (VW) can be the key to the reduction of the built environment impact. Because the total water consumption of a building includes not only the water that has been required off-site to manufacture the materials used, as well as the water embodied in the production of energy, also the direct water used in the building needs to be studied. This together can be considered the building water footprint (WF). A methodology based on the quantity surveying of the building project which includes materials and machinery is used for the inventory. The WF quantification is treated similarly to a project budget. A case study of a residential building in Huelva, Spain is evaluated. The most impacting stage is the use followed by the construction, being other stages less significant.