A number of homes have been flooded and thousands more are without water after a mains pipe burst in Burgess Hill.
West Sussex Fire and Rescue Service was alerted around 4am that the pipe had burst, flooding water into Cromwell Road.
Homes in Fairfield Road, Newport Road and Royal George Road were also affected.
Four fire engines attended the scene and directed water to a nearby field.
The subsequent repairs have meant that water has temporarily been cut off to 3,500 homes while South East Water engineers repair the main.
The clear up operation is now under way after a number of homes were breached.
Some residents have been moved after their houses flooded destroying carpets, furniture and belongings.
South East Water posted a statement on their website:
Our technicians are on site and have stopped water flowing from the main to allow us to clear the water and to start our repairs.
A delivery of bottled water is due to arrive later this morning at the junction of Cromwell Road and Park Close.