A construction error associated with Loudoun County’s ongoing Rt. 7/690 interchange project caused the waterline break that left Purcellville residents and businesses under a boil water advisory this week.

The waterline broke twice on Sept. 8 as work continued on the County interchange project. Town crews completed repairs to the first break on Tuesday afternoon and restored the waterline to full service after the second break at noon on Wednesday, but residents must continue boiling their water while required testing is completed.

“The break was due to an error with the ongoing construction by the county’s Rt. 7/690 interchange project,” the Town said in its Wednesday update. The water line breaks occurred east of Hillsboro Road, between Leesburg Pike (Rt. 7) and Centerfield Farm Parkway.

Although the line itself has now been repaired, the construction-related break triggered a water-quality testing process that is expected to keep the boil water advisory in place until at least Friday evening and possibly Saturday.

Following repairs, Town staff flushed the water system and began collecting samples throughout the distribution system. Those samples are being delivered to a certified laboratory, with initial results expected approximately 24 hours after testing begins.

One satisfactory round of testing will not be enough to lift the advisory. After the first results are received, Town staff must collect a second round of samples and have those tested as well. The boil water advisory can be lifted only after both rounds confirm that the water is safe.

As a result, the Town said the earliest residents can expect the advisory to be lifted is Friday evening, Sept. 11, or sometime Saturday, Sept. 12.

The disruption comes as Loudoun County moves forward with construction of the Rt. 7/Rt. 690 interchange project, a major transportation project affecting the Purcellville area.

While the immediate waterline damage has been repaired, the effects of the construction error will continue for residents and businesses until the required testing is completed and the Town determines that the water is safe for normal use.

The construction-related break also disrupted local businesses, with many Purcellville restaurants forced to close because of the boil water advisory.

Although the waterline itself was repaired and returned to full-service Wednesday afternoon, the effects of the break will continue for residents and businesses while the Town completes the required water-quality testing.