Scores of people faced problems this morning when one of the town's main water pipes burst.
The A689 is closed on Belle Vue Way between Brenda Road and Burn Road because of the flooding and police are urging motorists to take an alternative route.
The nearby streets have also been affected by the flooding and many homes were left without water.
Emma Staples, a spokeswoman for Hartlepool Water, said crews are working hard to get things back to normal as quickly as possible.
She said: "We’re very sorry for the disruption caused to customers in Hartlepool who have been affected by a burst to an 18-inch water main this morning.
"This is one of the key water mains serving Hartlepool and in order to repair the pipe and road we’ve had to close the A689 dual carriageway.
“Our teams have been working since 2am to restore water supplies to those served by this pipe, and we have managed to reroute water around the damaged section to bring everyone back on.
“Unfortunately, the escaped water has caused flooding to some properties in immediate area. Our contractors will be visiting each customer today and we will pick up the tab for putting things back to normal for them.
“We do know St Aiden’s School and some customers in Mainsforth Terrace are still without water. This is a result of the sudden depressurisation causing bursts in other connected areas. We will be speaking to those customers this morning and getting them back on water as soon as possible. We will also be providing bottled water to St Aiden’s School.
“We know how distressing flooding can be, and how disruptive it is to be without water or face an emergency road closure, so we are very sorry for the inconvenience this will have inevitably caused.
"This is our top priority and we will be pulling out all the stops to get things back to normal and reopen the road as quickly as possible."
Regular updates will be provided on www.hartlepoolwater.co.uk and via Facebook.