Traffic has been reduced to one lane between Centennial Drive and Walford Road, where the watermain broke. The crew dug a large hole to reach and repair the watermain.
The city said construction is expected to be completed prior to rush-hour traffic on Thursday morning.
In June, a watermain break on Elgin Street, in downtown Sudbury, created a large sinkhole.
A watermain break also reduced the Kingsway to one lane last December.