LAUREL, Md. (AP) — Washington’s Maryland suburbs have 350 miles of large concrete water pipes that are prone to exploding without warning, an inventory that’s second only to Detroit’s among major utilities, a newspaper has found.
The Washington Post reviewed 21 large utilities and found that the Washington Suburban Sanitary Commission has two to three times as many large concrete water mains as many other U.S. cities and suburbs.
The mains are designed to carry high volumes of pressurized water and are supposed to have a 100-year lifespan. Many were installed in the 1970s, when less strict industry standards allowed for the installation of pipes that were more likely to break. Utilities around the world began struggling with the style of pipe in the 1980s.
Nine of the WSSC’s mains have blown apart since 1996, including one that exploded this spring along Connecticut Avenue in Chevy Chase. Other major explosions occurred in 2008, when motorists had to be rescued from water flowing down River Road in Bethesda, and in 2011, when doors and walls were blown out in a Capitol Heights office park.
The pipes are up to eight feet in diameter. When they explode, they can leave 50-foot craters in roads and hurl debris “like shrapnel,” said Gary Gumm, the WSSC’s chief engineer.
Replacing the pipes would cost $2.9 billion, a move that doesn’t make sense because inspections have shown that only 1.5 percent of concrete pipe sections need to be repaired or replaced, WSSC officials said.
The WSSC denied requests by The Post for maps of the mains’ locations, citing homeland security concerns.
The utility has spent $21.2 million since 2007 on a detection system that’s meant to alert the utility about weakening pipes. WSSC officials said they have averted two potential explosions that way.
(Copyright 2013 by The Associated Press. All Rights Reserved.)