Pecan Street is close to installing something they refer to as the Blue Cube on houses in their monitoring program. Blue Cube works in conjunction with a fancy meter register at the street to report water consumption on a gallon-by-gallon basis. In other words, each time you use a gallon, the meter reports it to the Cube with a timestamp. In this way, you (and Pecan Street [and perhaps the city]) can track the details of your water usage.
There's the cube!
The hope of the detail measuring of water usage at the street is that the overall signal can be decomposed into telltale component parts. For example, the flushing of a toiler has a tell-tale signal: a certain number of gallons over a certain amount of time. The same for a shower (although shower times can vary) and other water-consuming activities. The hope is to be able to see where water consumption is occurring and how changes in technology (adding dual-flush toilets) and policy (drought restrictions) impact water consumption.
We're signed up, so hopefully we'll get cubed! I'd like nothing better than being able to track water consumption on a gallon-by-gallon basis!