Fresh water scarcity in arid regions is well acknowledged. Sources of urban water in the United Arab Emirates (UAE) are groundwater, desalinated water and treated wastewater. In the Emirate of Abu Dhabi (EAD), about three-quarters of the costly desalinated water supplies are used for irrigation to amenity plantations and for home gardening (Environment Agency Abu Dhabi, 2009). The per capita water consumption in EAD ranges between 170 and 200 lpcd in flats and between 270 and 1,760 lpcd in villas. The amenity (park, gardens and recreation areas) irrigation has been increasing in the region with the rapid growth of its urban development. Currently about 98% of wastewater generated from households in EAD is centrally collected through an efficient sewerage networks and then treated for reuse in the irrigation to roadside plantations and public places. In current practice, treated sewage effluent is not conveyed for domestic gardening and toilet flushing purposes. This is because of necessity of dual reticulation system that will increase the marginal cost of water supply significantly. Greywater collected from shower, ablution, washing machine, bathroom sink and other household activities (except from toilet and kitchen source) are generally less contaminated than that of municipal wastewater and can be reused for non-potable consumptions (Mourad et al., 2011; Friedler and Hadari, 2006)
