"A large concrete water main that exploded this spring along busy Connecticut Avenue in Chevy Chase has brought to light a little known local distinction: The Maryland suburbs have more of a notoriously problematic stock of pipe than almost any major U.S. water utility."
"The Washington Suburban Sanitary Commission has 350 miles of concrete mains that have been prone to exploding without warning. The particularly large mains are designed to carry high volumes of pressurized water. Utilities around the world have struggled with this type of pipe since the 1980s, when they began bursting decades before their 100-year life expectancy was up.
The WSSC’s inventory of large concrete pipe is second only to Detroit’s and two to three times that of many other U.S. cities and suburbs, according to a Washington Post survey of 21 large utilities."