Water Saving in Domestic Car Washing

There is considerable interest in promoting domestic water efficiency. A wide range of studies have focused on water saving within the house, both by technical means (low flush WCs, reduced flow in showers, etc.) and by changing user habits. However, rather less attention has been paid to water use outside the house. One of the activities that uses water outside the house is car washing. Much is known about water use in commercial car washes but relatively little about domestic car washing. The aim of this study was to gather information about the water used for this activity. Key questions were whether the wash is done in a commercial carwash or at home, and, if the latter, what is the volume used per wash and the frequency of washing? As part of this trial the use of water on different types of cars using different washing regimes was measured. From the study conclusions are drawn about the likely water use for domestic car washing.