WSSC proposes new building limits near potentially explosive water pipes

The water utility for Montgomery and Prince George’s counties says its largest concrete pipes are potentially so dangerous if they burst that all new buildings within 80 feet of the underground mains should be required to be fortified to withstand explosive forces.

Officials at the Washington Suburban Sanitary Commission say they need to protect people in future homes, schools, offices and other new buildings from the largest of their aging pipes — five of which have succumbed to “catastrophic failure” since 1996. The highly pressurized water mains, some of which are so big they could accommodate a minivan, explode with the force of 20 to 200 pounds of dynamite and spew water at up to 90 mph, according to a WSSC analysis.

No one has been seriously injured in a break, but WSSC officials say they’re concerned about recent close calls. Firefighters and police had to rescue stranded motorists from a torrent of frigid water when a 66-inch main burst along River Road in Bethesda in December 2008. When a 54-inch pipe burst in a parking lot of a Capitol Heights office park in January 2011, the blast of water blew off doors and ripped out walls. Nearby workers said they thought a bomb had gone off.

“If you’re going to build in an earthquake zone, you have to take into account an earthquake and how buildings would survive it,” said Gary J. Gumm, WSSC’s chief engineer. “This is similar to that.”

But developers are pushing back, saying an 80-foot setback would severely restrict use of their land and probably would require more expensive construction. If WSSC is concerned that its pipes pose a danger, they say, the utility should pay property owners for land needed to provide a safer buffer.

WSSC’s six commissioners, who are appointed by the two county executives, are scheduled to vote on the issue as early as June 20. A public hearing on the setback proposal is scheduled for June 6 at 7 p.m. at WSSC’s headquarters, 14501 Sweitzer Lane in Laurel.

Two of the large mains, including one that is almost 70 years old, run through the 488-acre site planned for apartments, condominiums and townhouses in the new Konterra Town Center East near Interstate 95 in Prince George’s.

“They have right of way for their pipes, and we can use our land up to their right of way as we see fit and the county allows,” said Caleb Gould, the project’s developer. “If they want us to fortify buildings because they have a dangerous pipe in their right of way, we’d need to be compensated for that.”

Asked whether he would be nervous about building homes near a potentially dangerous pipe, Gould said, “I’m not nervous because WSSC is liable for [its pipes]. They’re the guys who are supposed to keep their pipes safe.”

WSSC officials say the agency and water utilities nationwide began seeing breaks in the larger concrete mains in the 1970s because water seeped through pipes’ cracked concrete walls and corroded reinforcing steel wires. WSSC has 145 miles of such pipes throughout both counties.

The setback requirement also would cover 18 miles of large cast-iron pipes, which haven’t posed a problem but can be brittle, Gumm said.