The temporary traffic lights on Warwick Road will be removed over the Christmas period. United Utilities say the road will remain clear until after New Year, when a decision will be made on how to complete the final stages of the scheme.
The works to refurbish pipes under Warwick Road began in January, and were originally due to finish in June. But the project ran into problems when a section of pipe lining caused setbacks.
A spokesperson for United Utilities said "There are two water mains on Warwick Road. We have now finished working on the eastbound side of the road which has been particularly challenging because of difficulties with the pipe lining. All our traffic management is now gone and we are off site until at least after New Year.
"Some time next year we will start work on the water main on the other side of Warwick Road and we are in discussions with the council about when that work can start.
“We want to thank everyone for their patience while we have been refurbishing one of Carlisle’s key water mains. Although we had some difficulties with the work we are now satisfied that the new pipe lining meets all the required standards which means better water quality for people in the city. We are clear of Warwick Road now over Christmas and New Year."
Drivers have faced months of disruption on Warwick Road, as long queues have delayed motorists in both directions.
Many residents have spoken about their frustration over the delays and traffic congestion.