A paving project that started two months ago on Ocean Street in South Portland remains incomplete because the Portland Water District plans to replace a water main in front of Mahoney Middle School in September.

The mile-long paving project, from Broadway to the Cape Elizabeth line, started June 22 and was expected to be completed by the end of July, according to the Maine Department of Transportation.

It’s a heavily traveled stretch of Route 77, where commuter backups are often evident at intersections with Broadway, Highland Avenue and Sawyer Street, especially when school is in session.

Glidden Excavating & Paving of Gorham completed most of the paving project several weeks ago, except for the section in front of Mahoney Middle School, where Ocean Street meets Broadway. Travel lanes have been painted, but the pavement appears to be a base layer and barrels mark the unfinished median strip.

Glidden is waiting for the water district to replace a water main that recently broke and was temporarily fixed, according to state transportation and water district officials.

The water district advertised the water main project and opened contractor bids last week. Work is expected to start the first week in September and take three weeks. Glidden will return to complete the $438,000 paving project as soon as possible.