It's becoming a common scene in London, city works crews digging for a frozen pipe.

London Water Supply manager Dan Huggins say there have been more than 400 cases of water service pipes freezing over the last few weeks, the most ever in London.

It means all those homes go without water until a crew can get to them.

"Crews are first excavating down to expose that service pipe. Then they can cut into it, then we have a hot-water injection system which will then thaw the ice that was formed inside the service pipe, and we can restore it to normal service," says Huggins.

It's a tough job for sure in the bitter cold.

Crews say it can take as little as 10 minutes or it has taken as long as five hours to thaw out frozen pipes.

In some cases, the frozen pipe extends all the way across the road close to nine metres.

But they're aren't enough resources to keep up and in some cases, a temporary measure is taken.

"So this comes out of his outside tap and it comes through the blue hose and into my outside tap. So we're basically back-feeding my house from the outside tap," says homeowner Peter Veel.

This is the second year in a row Veel's pipe has frozen.

Last year it took five weeks to come back to life.

"I live alone and I'm away quite often on the weekends and different things. So I don't have a lot of water usage so the lack of water usage probably contributes to my line freezing," he says.

Lucky for him, his neighbour doesn't mind.

"I've been living here 47 years and it's never been froze up before but the last two years it has been," says neighbour Fred Vollick.

Huggins says there are no extra costs to homeowners to get water running again.

"We're doing all we can. We're working seven days a week. We've got our crews working late nights after midnight. Our guys are out here in the bitter cold doing their best to get the water back on for people," he says.

Luckily, warmer temperatures are in store for London starting on the weekend.