Are you wondering how much water your household uses? The Pacific Institute offers a great free tool to estimate your homes energy use. I went through the survey and the website gave output many pages of statistics, figures and tables. It appears that the pacific institute's ultimate goal is to help us realize the embedded energy that we move through when we use water. Embedded energy is the total energy used by a utility to collect, treat, and distribute water to the customer and to treat wastewater.
The calculations have many assumptions built in. I was battling it's assumptions for leaks, but then I read the fine print. The website operates on the assumption from an AWWARF study finding that states nearly all houses have leaks. The study, Residential end uses of water is linked here.