IN-DEPTH ANALYSIS OF 400,000 MILES OF WATER MAINS IN THE US AND CANADA
Utah State University (USU) report examines break rates and related factors such as pipe material and diameter
FULL REPORT
Deteriorating Infrastructure, Municipalities and the people they serve depend on pipe networks that provide safe drinking water. This piping is underground, out of sight, and often neglected. Overall assessment of water infrastructure condition is not good. Using the US as an example:
In 2009, the American Society of Civil Engineers (ASCE) issued a US report card and gave a D- to drinking water infrastructure.
In 2017, the grade improved to a D.
In 2021, the grade was raised to a C-, better but still not good.
Utilities are currently losing 11% of their water to leakage.
Pipe life estimates of 75 to 100 years contrast with an average replacement schedule of about 200 years (ASCE, 2017). The American Water Works Association (AWWA) has also reported on water main replacements in the US. In the annual AWWA State of the Water Industry Report, renewal and replacement of aging water and wastewater infrastructure was listed as the top concern (AWWA, 2017). This has remained a primary issue for utilities nationwide for the last five years (AWWA, 2023).
Deteriorating water mains are threats to the physical integrity of distribution systems, causing adverse effects on flow capacity, system pressure, and water quality (Grigg, et al., 2017). In addition to maintenance requirements and economic impacts, consequences of a broken water main include local flooding, interruption of water delivery, and damage to roads and private property. These outcomes also negatively affect a utility’s customer satisfaction.
Utility data clearly indicate that the integrity of water pipelines in the US and Canada continues to deteriorate as the infrastructure ages. Among the many indicators of aging pipes, break rates are the most significant.
Break rates for each utility can vary from year to year and even seasonally. Over time, however, break rates for specific pipe materials are consistent. This consistency is one reason why break-rate information is so important. This comprehensive study of water main break rates uses input from 802 utilities to compile an accurate data set for making pipe-replacement decisions. Highlights of the study:
Break rates of all pipe materials remain consistent when compared to previous USU studies.
The current study received a wide distribution of responses across utility sizes.
In the past five years, total miles of asbestos cement and cast iron pipes have been reduced, most likely being replaced with materials such as ductile iron and PVC.
The replacement of asbestos cement and cast iron pipe is creating a shift in predominant pipe materials in several regions.
Pipe performance is impacted by soil corrosivity.
There is a significant correlation between water main breaks and pipe material as well as diameter
The report summarizes one of the most comprehensive and statistically significant water main break studies ever accomplished on underground infrastructure. The study focused on water main material, pipe diameter usage, age, trends in material use, break rates, effects of soil corrosion, and utility size characteristics in the US and Canada. The study was successful in getting 802 participants to respond to a basic survey and 172 utilities to respond to a detailed survey. The primary goal of the study was to obtain average values for water main break rates by pipe material and diameter.
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