This study commissioned by the Environment Agency explores effective ways of increasing water efficiency in existing homes in South East England, building on findings of an earlier study. Following a pre-selection process, five demand management measures were analysed in-depth. Results indicate that average incremental social costs of retrofitting water efficiency measures compare favourably with the costs of traditional resource development schemes. The highest water savings would spring from a combination of different measures. The study also highlights that water savings increase significantly with only a small increase in cost if full subsidies and free installation are provided as part of the ‘package’.