This report outlines a water efficiency trial that Wessex Water undertook together with Somer Community Housing Trust, the Environment Agency and Resource Futures. The trial involved assessing the uptake, effectiveness and costs of different water efficiency activities in 24 blocks of social housing flats in Bath. Blocks were split into four groups, each receiving different educational and technical water-saving measures. Uptake rates amounted to 45% for dual flush devices and 50% for engagement activities. Where interventions took place, up to 14% less water was used. The device interventions appear to be more effective than educational engagement.