As reported in the Evening Times, the burst water pipe has angered shopkeepers in Glasgow's St Vincent Street and nearby West Nile Street and Renfield Street.
Scottish Water, which was told of the leak six days ago, has been trying to repair the damaged valve without disrupting supply.
But last night it revealed it would have to shut off the water overnight to carry out the "extremely complic-ated" procedure.
Jim Hassan, Scottish Water's operations manager for Glasgow, said: "Our engineers have been using all their experience to identify the best possible route to complete this repair without affecting water supplies.
"This work will help us to significantly reduce the area which will be impacted.
"It will however still be necessary to shut off supplies. To reduce disruption repairs will take place overnight, with supplies shut off after midnight.
"We would like to take this opportunity to apologise for any inconvenience."
Engineers had been working around the clock to carry out the repair in St Vincent Street before discover-ing they would need to shut off the supply.
Customers in the Trongate, Gallowgate, Calton and Bridgeton areas were all to be affected when supplies were shut off last night. They were due to be restored this morning.