Growth in population and households, and lifestyle changes are factors placing water resources under increasing stress in some parts of the UK. The Code for Sustainable Homes (CSH), a government regulation defining performance standards for new dwellings, is one measure that may act to counter rising domestic water demand. One goal of the CSH is to reduce potable water use per capita in each home through implementation of water conservation measures. This paper reports on work in progress that aims to understand the likely impact of the CSH on regional and national water demand. A spreadsheet model is being developed to assess domestic water demand under a range of CSH uptake scenarios, as well as a range of demographic, technical, economic and behavioural aspects of water consumption and conservation. The paper discusses the model development and presents some preliminary results for the Yorkshire region.