City of Falls Church utility workers and a contractor work at the intersection of Shreve Rd and 29. (Photo: Courtesy Barbara Gordon)

Two lanes of I-495 that had been closed due to the water main break repairs under the road were reopened around noon today.  As of 9:30 p.m. last night, the 10" pipe under 495 was  completely capped off and all customers were back to full service.

By 11 p.m. last night the back filling along 495 ( the excavated area ) was completed.

This morning the contractor laid the asphalt and the paving was completed around 11 a.m. with all lanes reopened by noon.

Falls Church City, 5:30 p.m. -- Falls Church City utility operations crews have identified the location of the water main break which occurred early this morning morning under I-495 where it passes under Rt 29 in the Merrifield area of Fairfax County.

Two lanes of I-495 are still closed but crews hope they can be reopened by tomorrow morning.  Water pressure is stable and adequate in areas of Merrifield and Fairview Park which had low or no water pressure immediately after the break.

The broken pipe is located about 11 feet underground and is 10" in diameter and made of cast iron.  The cause of the break is still unknown.

UPDATE: 1 p.m.: Falls Church City utility operations crews are investigating the cause of an early morning water main break under I-495 where it passes over Rt 29 in the Merrifield area of Fairfax County.

The break occurred early this morning, causing water to flow over all four lanes of the Beltway and slowing traffic.  The broken pipe has been shut off, stopping the flow of water. An exit ramp and one northbound lane on the right side of I-495 are still closed, and may remain closed most of today.

Motorists can expect delays on the inner loop through the afternoon rush hour and possibly during tomorrow morning's rush hour.  Water pressure has been restored to areas of Merrifield and Fairview Park which had low or no water pressure immediately after the break.

A contractor is on site and digging down to the pipe, which is located about 11 feet below ground.  The pipe is 10" in diameter and made of cast iron.  Cause of the break or how long it will take to make repairs is still unknown.

Falls Church City - Thursday, November 12, 2009 9 a.m. - Falls Church City utility operations crews are working on a water main break under 495 where it passes over Rt 29 which occurred early this morning.

The pipe is 10" in diameter and made of cast iron.  Crews have located the valve so the water flow is stopped but they do not yet know the cause of the break or how long it will take to fix.  As of this writing, three northbound lanes on 495 are open and only the two shoulder lanes remain closed between Rt 50 and 29. Earlier this morning some areas of Fairview Park were without water but separation valves have since been opened to provide water to areas with low or no water pressure.

The pipe is 11 feet under ground, so will take some digging to determine the exact location and cause of the break.  Miss Utility has been called and no digging can begin until Miss Utility has given the all clear sign.  A contractor has also been called in to do the excavation.