Household Forecasts for the Planning of Long‐Term Domestic Water Demand: Application to London and the Thames Valley

Methods for forecasting households in London and the Thames Valley were developed for input to forecasts of domestic water consumption. Households were forecast by ethnicity, size and property type. South Asian‐headed households consumed more water (per capita) than average. Forecast populations for 60 Local Authorities were extracted from a UK‐wide forecast and aggregated to six Water Resource Zones (WRZs). Household populations by age, sex and ethnicity were multiplied by trended headship rates to forecast households. Households were classified by size and property type using census microdata. Water demand was generated using modelled consumption rates, based on policy interventions. Between 2011 and 2101, the region will experience 85% growth in populations and 113% in households. The household growth will vary across WRZs between 54% and 126%. Water demand in London and the Thames Valley is forecast to grow by 90%, 69% and 46% under status quo, moderate and extreme conservation scenarios. The future growth in water demand under all scenarios poses a huge challenge for the region, already under water stress.