Income inequality in Germany has been continually increasing during the past 20 years. One cause of this development, among others, could be structural shifts in household formation due to long-term societal trends. These affect per capita incomes, which has repercussions for the income distribution even if wages remain constant. The aim of this paper is to quantify the proportion of changing household structures in the increase in inequality. We find that the growth of the income gap in Germany (for both East and West from 1991 to 2007) is indeed strongly related to changes in household structure and employment behavior, and a large part of this increase is compensated by the welfare state.