"Our team will be setting up lighting etc to work in the dark, and again, we ask for your understanding as we deal with this interruption."
A small number of properties had been left without water.
"Our staff are out there now, and we'll aim to have this repaired as soon as possible," the spokeswoman said.
In the meantime, residents in the Bluff Hill area were asked to conserve water yesterday afternoon.
While most homes would be serviced by the council's other mains, the spokeswoman pointed out that pressure might be lower than normal.
Unison relationship and customer care manager Danny Gough said work was under way to upgrade underground cables at that location.
"Whilst that work is being repaired we have subcontracted a company to do some drilling on our behalf, and from what i gather, as they have gone through with a drill, it has picked up a rock and the rock has moved and impacted on the water main and caused the damage. Unfortunately, that's caused a bit of a mess."