Water System Leakage Assessment and Reduction

Water Conservation Action No. 6 - Assess and reduce water system leakage

Water providers must identify methods to reduce leakage in their systems, and to reduce unbilled water. Each water provider should perform a distribution system water audit based on the International Water Association (IWA) methodology, in order to maintain uniform assessments of leakage and set targets at the economic level of leakage. Further information on the IWA Methodology can be found on the American Water Works Association (AWWA) Web Site.

Why Use IWA/AWWA Methodology?

The IWA/AWWA methodology is recommended because it addresses some of the major problems in estimating system water loss. The commonly used percentage of “unaccounted-for-water” method of determining system water loss does not provide a standard for measurement of water use and water loss. 

The IWA/AWWA methodology defines all uses and losses and is designed to function with different units and measures using a water balance format.  The result is an infrastructure leakage index (ILI) which is a ratio of Actual Real Loss to Unavoidable Real Loss.       

Why are Leak Detection and Repair Important?

The assessment of water loss and the reduction of water system leakage through water system leak detection and repair is the largest source of water conservation savings in the District Plan.

In 2005, the American Society of Civil Engineers’ “2005 Report Card for America’s Infrastructure” also reported that 6 billion gallons of water per year is lost. The findings of each study state that the 6 billion gallons lost is enough water to serve 10 of the largest U.S. cities or all of California, respectively.

A leak detection and repair program to recover lost water may benefit the water provider in many ways because recovered lost water

  • may delay the need for developing new water sources and infrastructure
  • is treated and ready for use by the customer
  • is pressurized to reach the customer
  • may generate additional revenue
  • conserves energy (Source: OnTap Spring 2006)

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