Around 3,000 homes and businesses were left without water today after a burst on a major pipe which supplies a pumping station.
Yorkshire Water said it hoped to fix the problem in the Thirsk area within hours, after customers found around 8.30am that their supplies had been cut.
A spokeswoman said: "We apologise to any customers in the Thirsk area who are currently without water due to a burst water main this morning.
"We are working as quickly as possible to carry out repairs to the pipe and hope to have this completed as soon as possible.
"Once the repairs are complete water will start to return to homes, which we expect to happen in the next few hours.
"When water supplies do start returning we would ask customers to use their water sparingly to allow the system to fully recharge as quickly as possible.
"Again we apologise for any disruption that this burst may have caused to customers in the area and thank them for their patience."
A pipe into a pumping station serving Thirsk burst last night and a by-pass was put in place overnight, but when customers demanded water in greater amounts this morning, the temporary system could not cope.
Meanwhile, a major repair operation was swiftly put into action after a burst threatened part of the route of the London 2011 New Year Parade.
The spectacular involving 10,000 performers from 20 countries is watched by 100 million Americans on television as it passes through central London.
A burst water main in Victoria Street, near Great Smith Street, caused the road to be closed off to traffic yesterday, threatening to disrupt travel for revellers and potentially diverting the route of the parade.
Thames Water was praised by Westminster Council for quickly getting a team to the site who spent all day on the repair.
Work to rebuild the road over the top of it is expected to be completed today.
Martin Low, Westminster Council's City Commissioner of Transportation, said: "This helped save the parade, which will be watched by 100 million Americans, from disaster."
The latest burst follows a spate of problems around the country, as the big thaw caused damage to the water infrastructure.
Since Christmas Eve alone, one company was deluged with 40,000 calls reporting problems.
United Utilities, which operates in the North West, said the "unprecedented" volume of calls was 10 times the usual number.
Melting ice can cause the ground to move, putting stress on pipes, making them leak or burst.
Above ground, frozen pipework in homes and businesses is beginning to thaw, leading to more leaks.
Customers have jammed phone lines reporting frozen pipes in their own homes, although companies are not responsible for pipes inside people's houses.
The thaw has caused acute problems in Northern Ireland where thousands of customers' supplies have been cut off.
It could be early next week before all customers are reconnected.
Around an extra 250 megalitres are being pumped into the system every day, Northern Ireland Water said today, but most of it is being lost in leakages from burst pipes.