Trenchless Technology & Subsurface Construction

Chapter 7

Unaccounted for Water

Unaccounted-for Water (UFW) is the difference between the quantity of water supplied to a city's network and the metered quantity of water used by the customers. UFW has two components: (a) physical losses due to leakage from pipes, and (b) administrative losses due to illegal connections and under registration of water meters. While every case is different, often both components contribute roughly equally to UFW.

The process to determine unaccounted-for water can be summarized in three steps:

• Totaling the volume of water produced or supplied to the distribution system, as measured by all master meters at wells and treatment facilities or points of purchase from other utilities.

• Determining the volume of water sold and distributed as measured by sales meters and estimated un-metered uses.

• Subtracting the water sales and from the total water produced supplied will provide you with the amount of unaccounted-for water.

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