More than 20,000 people are without water after a large underground pipe burst.
Homes to the north and east of Nottingham were affected, with households experiencing low pressure or no water at all.
Severn Trent Water said it had no time scale for when people would see their supply fully restored.
The areas affected include Radcliffe on Trent, Bingham, East Bridgford, Upper Saxondale, Flintham and the village of Epperstone - where the burst occurred.
A car that had driven into the flooded hole caused by the high-pressure burst further "complicated" the repair.