article titled Characterization of greywater by appliance - Pattern of discharge along the day by Portuguese water scholars Cristina Matosa, Ana Sampaiob, António Sampaio Duartec, and Isabel Bentesa. Here are some of their "pollutographs" of greywater quality per domestic device. The first one shown here is the number of discharges per person through the day - this is the first time I have seen the water use data broken down by hour in the day. No surprises - peak discharges coincide with when we eat and it appears that I am not alone with the midnight trip to the WC.
The authors' conclusions? The proposed approach can be used to derive dry weather flow inputs to water quality. It also provides a mean to assess the impact of changes in household water consumption.