Bus travellers, drivers, businesses and residents were all affected when the pipe in Bridge Street, near Glasgow Bridge, cracked and opened a 16ft wide hole.
It's understood Bridge Street will remain closed until next Thursday.
The incident is the second time the same section of road has been affected by a burst main. In May 2006, a burst main caused an explosion, leaving a crater at the corner of Oxford Street and Bridge Street.
Glasgow City Council staff were at the scene today, inspecting the damage to the road, but the local authority could not confirm when the road would be able to reopen to traffic.
A spokesman said: “At this early stage, it is unclear when the road will re-open.”
People living in Bridge Street told of their shock when they realised the road had “cracked open”.
Terry Forteath, 36, was in his flat with his 12-year-old daughter, which overlooks where the main burst, when he heard the water gushing out.
He said: “We were just sitting in the living room and about 8.30pm I heared what I thought was loads of rain water.
“I looked out the window and saw water coming up from under the road, which had cracked open. It quickly started to look like a river.
“I saw a girl cycling through it and I thought if the lights went out she would fall in the hole.”
Scottish Fire and Rescue crews, along with police, rushed to the scene and closed the area, including Glasgow Bridge and Kingston Street.
Specialist engineers began expanding the hole to work on the large fractured pipe.
Water supplies had to be turned off, affecting thousands of homes in Shawlands, Pollokshields, Mount Florida, Newlands and Battlefield. Supplies were restored about 11pm.
Mr Forteath said water to his home was not affected, but he was one of several people to be evacuated. He said: “They told us we might have to get taken out the flat. I woke my daughter about 11.30pm and we got taken to the Spice Garden restaurant.
“The underground car park for our flats was completely flooded.
“They have been pumping out the water all night and this morning. It looked like a slipway last night.”
Sean Wight, who lives in Camphill Avenue, Shawlands, had his water supply cut for about four hours.
The 27-year-old, said: “I noticed the water was just trickling from the tap at about 8pm.
“Then our water was completely cut off. I couldn’t even brush my teeth last night.”
Knock-on effects from the burst meant some people woke this morning to find their water supplies had again been affected.
Mr Wight, an engineer, added: "Our water came back on overnight, but this morning I realised we had no water again. I had only enough time to have a shower before it cut out again."
Scottish Water bosses said any “isolated cases” of disruption today were likely to have been caused by “air-locks in the network”.
The spokesman added: “We will do everything we can to repair the damage and reinstate the road as quickly as possible.”