Officials from Montgomery and Prince George’s counties considering how best to protect the public from potentially explosive water mains have rejected a utility proposal to limit new building within 80 feet of the pipes.

In a meeting Monday, committee members said the Washington Suburban Sanitary Commission’s proposed setback was unwarranted, too broad and not cost-effective. The plan would have required that buildings within 80 feet of the largest mains be fortified to withstand the blast of a major break.

“The 80-foot setback requirement was a non-starter,” said Erv Beckert of the Department of Public Works in Prince George’s.

Several committee members said they were reassured by the group’s research, which found that the WSSC is considered a national leader in inspecting and monitoring its concrete mains. They said the public alarm and economic impact, such as potentially lower property values, that could result from a setback requirement didn’t make sense when WSSC inspections have found that less than 2 percent of the pipe sections have problems.

“The committee has come to recognize that the vast majority of WSSC pipes, even [large, concrete] pipes, are in good condition and have a lot of useful life in them,” said Diane Schwartz Jones, director of Montgomery’s Department of Permitting Services. “WSSC has a very responsible program for monitoring, inspecting and repairing its pipes.”

As Craig Shuman, director of construction for public schools in Montgomery, told the group: “Just because a pipe is adjacent to a building doesn’t mean there’s some tremendous risk with that particular piece of pipe.”

Instead, the panel will recommend that the utility focus on pipes that could flood out large numbers of people, particularly in “vulnerable” buildings such as schools and hospitals. It also will recommend that the WSSC be more involved in the development review process for building proposals near the mains, and that the utility draft an emergency response plan for an event that could knock out the drinking-water supply.

The WSSC has 357 miles of concrete mains — some are big enough to accommodate a minivan — that serve as transmission lines, carrying water from filtration plants into communities. Because the pressurized mains carry such large volumes of water, a pipe explodes when it breaks. The setback proposal would have applied to 145 miles of the largest concrete mains, which are three feet or larger in diameter.

The utility, which provides water and sewer service to nearly 2 million people in Montgomery and Prince George’s, has had nine such breaks since 1996. It also has more of the problematic concrete pipe than almost any other major U.S. utility. Officials have said that the pipes are too big to move in the densely populated suburbs and would be too costly to replace completely.

The problem drew attention in 2008, when a pipe burst along River Road in Bethesda and motorists had to be rescued from the water. A break in 2011 blew off doors and flooded an office park in Capitol Heights. In March 2013, a break along Connecticut Avenue in Chevy Chase caused significant traffic delays on the major commuter route.

Unlike most decaying infrastructure, the WSSC’s concrete mains are not suffering from old age. They’re breaking decades before their projected 100-year-lifespan, often because of manufacturing flaws.

Utility officials have compared the need for a setback to special requirements for buildings in earthquake zones. They said that they were concerned about public safety, noting the rescues on River Road and the fact that injuries probably were avoided in Capitol Heights because the pipe burst at 3:50 a.m., when businesses were closed.

Utility officials have said that there are about 1,768 schools, homes and other buildings within the 80-foot zone.

On Monday, the bi-county group went beyond rejecting the 80-foot setback and recommended that the utility no longer have the power to require “special considerations” on some buildings within 200 feet of the pipes. Those decisions, the group said, are best left to local officials during the development review process. Instead, they recommended that the WSSC alert developers with building plans close to a large main.

In a discussion about improving communication with the public during a water crisis, some committee members pointed to confusion caused last summer when the utility warned part of Prince George’s to stock up on water because it needed to take a weakening pipe out of service. Two days later, after some businesses closed and stores ran out of bottled water, the WSSC called off the emergency, saying it had avoided the outage by fixing a valve.

Jerry N. Johnson, the WSSC’s general manager, told the panel that the utility has been working with the Metropolitan Washington Council of Governments to improve coordination to get emergency water supplies in place more quickly in the event of an outage.

“There was definitely not a plan for what you’d do if 100,000 people were out of water all of a sudden,” Johnson said. “It was very clear we were planning on the fly.”

Utility and council officials are working together to identify hospitals, nursing homes and other facilities that would need immediate attention, he said.

“We need another chapter in the emergency management book to deal with major water outages,” Johnson said.

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