Houses in Werribee went without water last Thursday after a burst water main caused a small sinkhole at the intersection of Derrimut Road and the Princes Highway.
Residents reported that the water main burst about 3pm, with nearby houses left without water for several hours.
However, City West Water managing director Anne Barker said the burst main was not reported until about 6pm.
Ms Barker said soil was washed away and a VicRoads traffic light control box and sections of the footpath fell into the hole.
Ms Barker said crews isolated the leak and diverted water supply to allow water to be reconnected to nearby properties. She said a temporary barrier was placed around the site to make it safe. Permanent repairs will take place over the coming weeks.
