Water main break rates have increased 27 percent in the past six years, with asbestos cement and cast iron accounting for a majority of that spike.

Those are some of the findings of a recent study released by Utah State University’s Buried Structures Laboratory, a follow-up to another study about pipe materials and water main breaks it did in 2012. The 2018 study included 300 utilities responsible for about 200,000 miles of water mains, covering 48 U.S. states and seven Canadian provinces.

“This report provides greater insight into the drivers of the aging water infrastructure crisis and offers data which utilities can use to benchmark pipe material performance. It will be a valuable asset management planning tool for water utilities,” says Dr. Steven Folkman, author of the study, noting that there was a 49 percent increase in survey responses compared to the 2012 study.

Some of the findings of the study:

• The percentage of water mains over 50 years old has increased from 22 percent to 28 percent in the past six years.
• The percentage of installed water mains that are beyond their useful lives has increased from 8 percent to 16 percent since 2012.
• Cast iron makes up the greatest share of the pipe material inventory, and 82 percent of all cast-iron pipes are over 50 years old. 
• Cast iron and asbestos cement make up about half of installed water mains, and since 2012 those materials have had break rate increases of 46 percent and 43 percent.
• Smaller utilities have twice the break rate of larger utilities.
• An average of 0.8 percent of installed pipe is replaced every year, which equates to a 125-year national pipe replacement schedule.
• PVC pipe has the lowest overall break rate when compared to cast iron, ductile iron, concrete, steel and asbestos cement. 
• Corrosion is a big factor in water main breaks, with 75 percent of utilities reporting corrosive soil conditions.

The full report is available here.