Assessing direct and indirect water requirements of construction

Australia is considered the driest populated continent in the world. Despite this, we consume the largest amount of water, per capita. While little of this water is used for the operation of buildings, buildings are now being designed to use less water. Additionally, rainwater collection and grey water recycling systems offer the potential to significantly reduce demand for fresh water. However, little is known about the water required directly and indirectly (ie., embodied in) construction materials and products. Embodied water comprises the water required directly for construction itself and the water consumed indirectly in the production and delivery of materials, products and services to construction. Water required directly for construction is likely to be insignificant compared to the indirect water required for the manufacture of construction materials and products (ie., through materials and other products required to support construction). There is currently a lack of research into embodied water requirements by the construction sector. The relationship between the embodied water and the operational water is also unknown, apart from a handful of studies based solely on national average statistics known as 'input-output' data. The aim of this paper is therefore to model the water required directly and indirectly by construction, integrating currently available public domain industry data with input-output data. The coverage of the industry data relative to the input-output data was evaluated for a typical commercial building, and was found to be very low.