scope:

Preface

Water main breaks are a primary cause of lost revenue and service for all water providers. Some water leaks make the evening news or the front page of the local newspaper. Others may go undetected until an unrelated excavation uncovers them or a mysterious soggy spot is identified and researched.

Main breaks occur regularly in drinking water distribution systems. Water providers experience about 240,000 water main breaks per year, according to a U.S. Environmental Protection Agency report about aging water infrastructure (USEPA 2007). Breaks interrupt service, often require costly repairs, pose the threat of contamination and the conveyance of waterborne disease, and cause customers to lose confidence in the water provider. The Report Card for America's Infrastructure (ASCE 2009) gives the nation's drinking water infrastructure a grade of D minus.

Some of the major contributors to water main breaks are identified in this guidebook. One of the primary issues facing water providers is the average age of the infrastructure and the importance of replacement. According to the USEPA (2002), "The useful design life of distribution system components range[s] from 65-95 years." The report further noted that the vast majority of the current underground water infrastructure in the United States was installed during the years just before through just after World War II, meaning the pipes will require replacement between the late 1990s and the 2030s.

Assessment and Renewal of Water Distribution Systems (Grigg 2004) identifies the variables that predict pipe failures. The author provides related distribution system statistics and reviews the science behind

water main breaks. The Water Research Foundation is currently organizing a National Mains Failure Database to document historic information on water main breaks from U.S. utilities to be compared with data from Australia and the United Kingdom.

Another major influence on the expected life of U.S. water infrastructure is the increase in the population. The U.S. population increased by approximately 159 percent in the last half of the twentieth century, and water usage increased by 207 percent, from 14 billion gallons to 43 billion gallons. This translates to a 20 percent increase in per capita use (average use per person) nationwide. The combination of an aging infrastructure experiencing an enormous increase in its originally designed usage and the other factors presented in this guidebook directly contribute to the realities of water main breaks.

This guidebook describes the causes of leaks, how to identify them, the effective use of information documented from main breaks, and, importantly, some cost-effective ways of making the repairs or managing contractors who are performing the work.