Thousands of residents left without water after a large underground main collapsed and caused a sinkhole should have supplies reconnected by tonight.
Severn Trent Water said repairs were due to be completed at about 7pm, after up to 20,000 are thought to have been affected by low pressure or no water at all.
The provider said if work to fit a replacement pipe was completed on time then supplies should be back to normal by 9pm, following a day of disruption.
Problems were reported in homes to the north and east of Nottingham after a huge main burst in the village of Epperstone creating a sinkhole.
A spokesman said that a car had driven into the flooded hole caused by the high-pressure burst, which had initially "complicated" any repair. He added that it had since been removed.
The woman driving the car was unhurt, according to the company.
Severn Trent Water said: "We are looking at getting the pipe fixed at 7pm tonight and that should mean everybody should get water back at 9pm, all being well."
Affected areas have included Radcliffe on Trent, Bingham, East Bridgford, Upper Saxondale and Flintham, with the company offering an apology for the widespread disruption.
The company said that it was looking at other ways to get water out to residents, particularly what it described as "our most vulnerable customers".
Severn Trent's spokesman added: "We've a register of the most vulnerable people and places, like hospitals - although I don't believe any hospitals are affected - where we can get bottled water, or bowsers or tankers if it's appropriate, out to them."
He went on: "Engineers are working as quickly as they can to restore supply."
The broken pipe set off a low-pressure alarm monitored by Severn Trent at about 4.50am and engineers quickly discovered the exact location due to the localised flooding.
The main is a large 24-inch (60cm) diameter pipe, which Severn Trent was able to isolate in order to initially put a few thousand homes back on supply.
Repairs were complicated after the driver of a Honda CRV found themselves in the gaping sinkhole which had opened up and flooded the road.
The driver managed to escape, and after the 4x4 was winched out, engineers were able to start repairs.
It is not yet clear what caused the burst.
Severn Trent said residents could contact the company on 0800 783 4444 or tweet @stwater.