Assessing minimum water efficiency standards for plumbing products in homes and business

This paper describes a study that used end-use-based stock modelling to develop water, energy and greenhouse gas (GHG) savings forecasts for policy options. These options were alternative mechanisms for imposing minimum water efficiency standards on the fixtures and appliances within buildings. The study demonstrates how both residential and non-residential sub-sectors can be modelled, using demographic and industry forecasts and other available data sources, using an end-use/stock modelling approach. Specifically, the study modelled the expected water, energy and GHG savings from potential minimum water efficiency standards for plumbing products and appliances in homes and business in Australia. It discusses the relative merits of mechanisms for implementing the proposed minimum standards via: a sustainable building planning measure – such as the Building Sustainability Index (BASIX) in New South Wales; the Australian Water Efficiency Labelling and Standards (WELS) scheme; or via plumbing regulations within the National Construction Code (NCC). The paper concludes that as well as being a useful mechanism for imposing minimum standards in itself, a star-rating system such as WELS offers advantages in developing and modelling water efficiency policy options. The approach described can support decision-making on policies that improve water efficiency across building types.