The Water Budget
This pattern is shaped by
Problem
Most households have no idea how much water they use, where it comes from, or where it goes. Without a budget — a clear accounting of inputs and outputs — there is no basis for conservation, no way to size rainwater systems, and no understanding of the relationship between the household and its watershed.
Evidence and Discussion
A water budget is simply a balance sheet: how much rain falls on the roof, how much water the household uses (and for what), how much greywater could be recycled, and how much leaves the lot as stormwater. The numbers are surprisingly accessible — a water meter, a rain gauge, and a weekend of measurement give you enough to design a closed loop.
Therefore
for every new dwelling, create a water budget — a simple accounting of water in (rainfall on roof, municipal supply) and water out (indoor use by category, irrigation, stormwater runoff). Use this budget to size the rainwater cistern, the greywater system, and the rain garden. Post the budget in the mechanical room as a reference. The household that knows its water is a household that conserves its water.