Abstract Household water consumption plays an important role in addressing the problem of water shortage and achieving sustainable water development. To identify, assess, and analyze the impact of a family structure on household water consumption, this study develops a mathematical statistical method to conduct multi-scenario simulations of average annual household water consumption based on data from the 2016 China Family Panel Studies (CFPS). The Kolmogorov–Smirnov test and the two independent sample t-tests were used to obtain the distribution with the highest degree of fitting, and the probability distribution and expected value of average annual household water consumption were obtained from the distribution probability function. The results demonstrated that the Birnbaum–Saunders distribution was the optimal distribution; families comprising one and two generations were dominant in terms of water consumption; and the number of water-saving households was far less than that of households with high levels of water consumption. The findings of this study have valuable implications for water governance and the domestic water planning.