Finding Lost Water

Aug. 18, 2011
The keys to preventing real and apparent water loss

About the author:

Craig Hannah, P.E., is development manager, Municipal Utility Solutions Team, for Johnson Controls. Hannah can be reached at [email protected].

Caitlin Cunningham is managing editor of Water & Wastes Digest. Cunningham can be reached at [email protected] or 847.391.1025.


Water loss in distribution systems—both real and apparent—carries a hefty price tag, and utilities across the country are experiencing or preparing for water shortages. WWD Managing Editor Caitlin Cunningham discussed this situation and potential solutions with Craig Hannah of Johnson Controls.

Caitlin Cunningham: How prevalent are leaks in U.S. water distribution systems?

Craig Hannah: Water loss is coming to the forefront as a challenge that affects U.S. utilities. Non-revenue water loss as a percentage of the volume supplied in distribution systems nationally usually ranges from 10% to 20%, but it is not uncommon for utilities to experience an even higher percentage of water loss. Research shows that approximately 80% of all real water losses can be attributed to leaks at service connections.

A government survey also shows at least 36 states anticipate local, regional or statewide water shortages by 2013. There are still many water utilities in the U.S. using wooden water mains that were installed during the 19th century, and it is also common for municipal systems to still use iron pipes that were installed more than 60 years ago.

Cunningham: What is the significance of this physical water loss to affected utilities? To the overall water industry?

Hannah: The U.S. Geological Survey estimates that water lost through distribution systems is 1.7 trillion gal per year, at a national cost of $2.6 billion per year, according to the U.S. EPA. In addition to the financial ramifications of inefficient water distribution systems, water scarcity makes effective water loss management a priority for many cities.

Cunningham: How do apparent water losses—those caused by inaccurate accounting of water use—factor in?

Hannah: Apparent losses are caused by many things, such as inaccurate water meters, improperly sized and typed water meters, human error in the meter reading and billing process, billing system errors and theft of service. Each utility should develop an appropriate water meter testing, repair and replacement policy. Large water meter services should be periodically reviewed to ensure the correct size and type of meter is installed for the application.

Some municipalities are still employing archaic recording systems through journaling each residence’s water usage in written documents, which lends itself to errors during the meter reading and billing process. Hand-held and touch-read devices are a drain on manpower, using cost-intensive labor and other resources. AMR and AMI systems greatly reduce apparent losses by removing human error. Additionally, AMI systems provide hourly usage data, which enables better consumer education of individual water use and reduces the ability for end-users to negotiate a disputed invoice.

Cunningham: What other leak prevention and apparent loss minimization solutions are available today? What benefits might end-users expect?

Hannah: Real water loss can be reduced through automated leak detection systems, pressure management programs and SCADA system optimization. Apparent water loss can be reduced through improving the accuracy of water meters, AMR/AMI systems, meter sizing and typing and reviewing the billing system. In addition, performance contracting provides an innovative method for financing these improvements. Periodic meter testing to ensure accuracy is another way of maintaining the water distribution system.

Consumers can realize several benefits from water loss optimization programs. Through AMR/AMI systems, municipalities and utilities can be better stewards of taxpayer dollars, reduce apparent losses and provide enhanced customer service.

Reducing water loss helps keep the cost of water down and saves energy, which ultimately improves the environment and promotes fiscal responsibility. Hourly usage data from an AMI system can help consumers find ways to conserve water and save money. Comprehensive leak detection systems also benefit consumers by helping utilities identify and repair leaks in an efficient manner, causing less disruption to daily activity.

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