With gridlock this evening on Swakeleys Road, Affinity Water told Hillingdon is Here the repairs were due to be finished tonight.
But the road closure will remain in place tomorrow, with officials expecting it to reopen on Friday morning.
The problems were caused by a burst in an 18 inch water main in Breakspear Road South, Ickenham.
About 25 residents reported problems with their water supply in their homes this morning.
Repair teams from Affinity Water were seen on site this evening, with water continuing to gush onto the road, not far from the junction with Copthall Road West.
The problem was reported to have occurred early this morning, since when police and water company officials have been on scene.
It has been reported elsewhere and by police that a 'sinkhole' had emerged but Affinity Water insisted tonight that this was inaccurate.
There were huge traffic jams arching back up to the top of Swakeleys Road tonight, as commuters were diverted.
Some cars continued to make their way down Breakspear Road South, despite the road closed signs.
But they found there was no way through with the barriers in place and were forced to turn around.
Sink hole on Breakspear Rd South, Ruislip pic.twitter.com/6Nr5aZx09t— Hillingdon MPS (@MPSHillingdon) 4 January 2017
An Affinity Water statement read: “Our technicians are continuing to make good progress on the repairs to the main which will be completed by the end of the day and we will aim to have the road restored by Friday morning.
“The road is currently closed to ensure the safety of commuters and our technicians working to repair the main. The repair to the water main should be complete by the end of today and we are currently assessing the damage caused to the road before restoration begins.
“Other media outlets have incorrectly reported this to be a sink hole, however it is simply just damage to the road caused by the burst.
“We would like to thank our customers for their patience whilst we carry out these essential repairs.”
The company stated: “We received 25 calls from customers who reported an interruption to their supply soon after the burst occurred, however water was restored by 8.15am.
“Our technicians were on site by 6.30am to shut down the main and begin repairs.
“We are sorry for any inconvenience caused.”