Twelve homes have been flooded and thousands of properties left without running water as a result of a burst water main.
The leakage occurred on a large water main on Stowe Heath Lane in East Park in Wolverhampton at about 0800 BST.
Severn Trent Water apologised to customers and said engineers were re-connecting more than 6,000 households using an alternative network of pipes.
Fire crews spent the morning pumping the water out from flooded homes.
A spokesman for Severn Trent Water said engineers were expecting to work until the early afternoon making repairs.
"Following a burst on a large water main on Stowe Heath Lane in Wolverhampton - Severn Trent Water is currently re-connecting over 6,000 customers using an alternative network of pipes," he said.
Stowe Heath Lane was closed while the repairs were carried out.