Access to water is vital for sustainable human socio-economic development. The study examined factors affecting households’ access to water supply in three residential areas in parts of Lagos metropolis, Nigeria. A random sampling technique was employed to administer questionnaires to 200 households. The study area was delineated into residential types using the grid method. The result shows the dominance of improved water sources in the high/medium-income residential areas. Households in the medium-income area recorded the highest access in terms of distance to, and safety of water supply. The factor analysis explains 77.41% of the variance with three components, namely: water access, demographic and economic attributes. The results of the analysis of variance reveal three significant variables, namely: main water source, income and cost, which is significant at p<0.01. The regression equation model obtained is given as Y = 2.059 + 0.307MWS + 0.286INM + 0.164CST. The study concluded that main water source, income and cost are the factors affecting access to water supply in the study area. The study recommends investment in water infrastructure, giving a higher priority to low-income residential areas for improved healthy living and sustainable socio-economic development.