At the top of the distribution license ladder, water loss stops being something you react to and becomes something you formally measure, benchmark against a technical minimum, and defend to a state agency with real numbers. This guide takes the water balance you learned at the Class 3 level and pushes it to full technical depth: the complete apparent- and real-loss breakdown used in a validated AWWA M36 audit, the Infrastructure Leakage Index that tells you how your real losses compare to what is physically achievable for your system, and the specific Colorado reporting framework that applies to larger utilities.
The Full AWWA M36 Water Balance
The IWA/AWWA water balance is the internationally recognized standard for water loss accounting, published in AWWA's M36: Water Audits and Loss Control Programs. At its top level:
$\text{System Input Volume} = \text{Authorized Consumption}