A collapsed major sewer line that runs through Montgomery County is spilling untreated wastewater into a creek bed and the Potomac River. DC Water, the utility that oversees the sewer line, expected the spill to be fully contained next week.

The approaching winter storm, however, may delay the completion of a bypass for the wastewater.

Drinking water in the region, which flows through a separate system, is safe and unaffected and no overflow has reached the C & O Canal Towpath, which remains open, said DC Water.

A section of the 54-mile Potomac Interceptor, which runs along the Clara Barton Parkway near Interstate 49, collapsed earlier this week.

The Interceptor handles up to 60 million gallons of wastewater a day, moving it from parts of Virginia and Maryland to the Blue Plains Advanced Wastewater Treatment Plant in Washington, D.C.

Residents near the affected area may notice odors from the overflow and the right, inbound lane on the Clara Barton Parkway, east of the I-495 interchange, is closed for construction related to the project.

The fix

DC Water planned to work with the National Park Service starting Thursday to remove the upper lock gates on the canal so it can accommodate a bypass for wastewater to flow around the damaged section of the sewer line.

The utility expected to begin redirecting wastewater as early as this weekend, which would significantly reduce the sewage overflow into the Potomac.

DC Water is rehabilitating the Potomac Interceptor through a 10-year, $625 million project to strengthen the most vulnerable sections of the sewer line, which is more than six decades old.

DC Water is urging the public to avoid contact with untreated sewage and to wash exposed skin thoroughly with soap and water.