Around 100,000 homes were left without water after a water main burst and caused a flood.
Scottish Water says it was impacting the water supply to around 100,000 properties in parts of the city of Glasgow and East Dunbartonshire.
Around 56,000 were restored by 9.30pm with teams continuing to restore the rest.
The force of the flood appears to have lifted the tarmac from the road.
Reports of interruptions were first made to the water company around 4pm on Tuesday, January 24.
Concerned Glasgow residents took to Twitter to complain about the problem.
One person wrote that his "entire street" in Glasgow had lost water.
Affected areas include the city centre, Tradeston, Ibrox, and much of the west end, including Kelvinside, Knightswood, Yoker, Scotstoun and Partick.
At 7.30pm, the company said the water main had been isolated and teams were working to restore water to 56,000 properties across Knightswood, Yoker, Scotstoun and Partick.
Flooding was seen on Auchenhowie Road in Milngavie and the surrounding area.
Scottish Fire and Rescue are attending the scene.
The local nursery Lullaby Lane also had to be evacuated and the staff and children taken in by Rangers FC at their Auchenhowie training ground.
A Scottish Water spokeswoman said: “This is a major burst which is impacting a lot of our customers and we want to reassure them we are working as quickly as possible to carry out this repair and restore supplies.
"We apologise to all customers affected for the inconvenience and disruption.
"Our teams are currently working alongside the police and fire service, and as soon as more information becomes available, we will be in touch."
Greater Glasgow police warned people to keep away from the are due to "significant flooding of the A81 (Glasgow Road) at its junction with the A807 (Auchenhowie Road) and the surrounding area."
A spokesperson for the Scottish Fire and Rescue Service said: “We are currently in attendance alongside emergency service partners at a water rescue incident at a junction between Glasgow Road and Auchenhowie Road in Milngavie, Glasgow. Operations Control mobilised two fire appliances and two water rescue resources to the area after the alarm was raised at 3.53pm on Tuesday, January 24.”
A Police Scotland spokesperson said: "Around 3.50 pm on Tuesday, 24 January 2023, police were called to assist with road closures following severe flooding on the A81 (Glasgow Road) at its junction with the A807 (Auchenhowie Road). A number of roads in the area have been closed and police are advising people to use alternative routes. Scottish Water is in attendance."
An update from Scottish Water confirms crews are in attendance at the burst strategic water main at Auchenhowie Road, Milngavie.
There's localised flooding as well as an interruption to approximately 100,000 customers' water supplies.
A spokesperson said: Our operatives are in the area supporting customers with the flooding, and we are making arrangements to isolate this water main to allow our teams to carry out a safe repair of the water main. Whilst we undertake these works, please be aware that some customers may experience no water, low pressure or discoloured water supplies.
"Once we have isolated this water main, we will work to introduce network alterations to restore customer water supplies as quickly as possible. We apologise to all customers affected for the inconvenience and disruption."
As of 10.35pm, Scottish Water had restored water supplies for around half of the properties across the city.
Around 56,000 were restored by 9.30pm with teams continuing to restore the rest.
