Traffic traveling both directions on Joppa Road in Baltimore County was backed up near Walther Boulevard on Thursday because of a large sinkhole.

The 12-inch water main break caused the street to collapse, said Jennifer Combs, a spokesperson for Baltimore City Department of Public Works.

“Crews are on-site conducting repairs, which are expected to be extensive and continue through the evening,” Combs said in an email.

To repair the water main, crews must shut down the main, excavate the damaged section, replace the pipe and restore water service, she said. Crews will restore the road after the repairs are complete.

Combs said 30 customers have been affected by the outage.

Baltimore County officials learned of the damaged road around 8:30 a.m., said Ron Snyder, a spokesperson for the Department of Public Works and Transportation.

The Baltimore City Department of Public Works was working with an on-site contractor on repairs because a water main break caused the road to collapse, according to a department spokesperson. The county handles initial installation and the city handles maintenance and repair as part of an agreement between the two jurisdictions.

The sinkhole — on the north side of Joppa Road just west of the intersection with Walther Boulevard — blocked at least one private driveway. A crew with an excavator could be seen at work just after 3 p.m.

Around 4 p.m., Baltimore County Councilman David Marks alerted people who need to travel west in the area to use alternate routes because only one eastbound lane can pass the sinkhole.

He said the sinkhole is about 100 feet away from where a water line was installed in 2019. But, he said, it was an older part of the water line where there have been breaks.

WJZ’s Stephon Dingle contributed to this article.