Water supply worldwide is facing pressure because of climate change and increasing water demand due to growing population and lifestyle changes. The traditional way of fulfilling the growing demand-supply gap by exploiting new fresh water resources and investing in the expansion of infrastructure is no longer considered environmentally or economically sustainable. The new path the water industry should follow is the management of water demand. Pilot residential efficiency initiatives are being launched by UK water providers over the past decade but despite the progress documented in this area, research on the evaluation of efficiency initiatives is still limited and little information is publicly available as to the magnitude of achieved water savings. Additionally, the need for establishing a robust evaluation framework is imperative.
The present study uses double case study methodology to evaluate the effectiveness of two residential efficiency programmes in reducing water consumption in areas where two UK water companies operate. Utilising household water consumption, weather and demographic data, it defines the factors that affect per capita water consumption via regression analysis. Employing reference groups of households that did not participate in the programmes and means comparison tests, it investigates differences in consumption between participants and non-participants during the programme period. The study continues by using multilevel models to accurately measure the water savings achieved through each programme and to define the factors that affect a household s potential to save water. It further produces an evolved framework for savings evaluation, providing detailed guidelines to water companies that want to embark on the evaluation of their efficiency programmes, taking into account various data availability circumstances.
Analysis illustrated a mean 6.95% decrease and a 14.7% decrease in consumption for each case study respectively, explicitly attributable to the efficiency programmes. Research findings provide strong evidence that single resident and financially stretched households have a bigger potential to conserve water and also highlight the robustness of multilevel analysis, even in cases of data limitations. This study provides invaluable guidance to water companies that aim to conduct water savings evaluation after an efficiency programme but also to the ones that are planning to embark into a new demand management initiative.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.