Few studies investigating the psychological determinants of water consumption and conservation use metered household water data. Studies that have used metered consumption have found that individual-level motivations are often weak predictors. This may be due to the psychological determinants being measured at the individual level and metered consumption at the household level. This article contributes to the water consumption literature by (a) identifying the determinants of change in water consumption over time and (b) testing effects in single-person households where levels of analysis are equivalent. We applied models to data from South Australia (N = 410) and Victoria (N = 205) and found that variables at the individual, household, dwelling, and regional levels predict the initial level of consumption and/or its rate of change. Some individual-level variables were not significant predictors of household consumption but did predict individual consumption. We discuss these results in light of previous research and offer avenues for future research.