An ongoing research project is aimed at producing microlevel population and domestic water demand estimates in order to help inform strategic, planning and other decision-making processes in the water industry. The need for a microsimulation approach arises because the United Kingdom has very few domestic meters in place. Thus, water companies do not know how much water is consumed by households and, or by small geographic region. Although water companies have registers of water passing through numerous supply points in the city, they do not know how it gets distributed at the small-area level or, indeed, how much is lost through leakage. Small-area estimates are, therefore, useful in their own right as information sources. When allied with population projections and the modelling of likely future trends in domestic water consumption behaviour, the resulting water demand forecasts can also inform strategic decision-making about the possible need for river abstraction, reservoir and water mains construction in the future.