Developing optimal policies on management of water resources, investment in relevant infrastructure and the protection of the environment requires data on the current and likely future demand for water services. In jurisdictions without water metering, information on the factors influencing demand tends to be limited. Microdata from household surveys can provide some relevant information. Domestic water demand is influenced both by the number of households and their characteristics, in particular the extent to which they employ water-using appliances. This paper focuses on domestic ownership of water-using appliances in the Republic of Ireland, a country where rapid economic and demographic change have put pressure on water and sewerage infrastructure but where there is little domestic metering. Using a large household micro-dataset, we use regression analysis to examine the determinants of the water and sewage mains connection status of Irish homes and to identify the characteristics of households that are associated with having larger or smaller numbers of appliances. Our empirical results suggest that Ireland will have a rising share of mains water and sewerage connections in the future. Household income, house price, dwelling types other than 'detached', younger dwellings, and urban location are all positively associated with having a mains connection. The number of types of water-using appliance in a household is positively associated with income, house price, number of residents, owner-occupation, having children (or, to a lesser extent, multiple people) in the household, having a detached house, being located in a rural area and living in a dwelling built after 1997. © 2010 The Author(s).