Residents in Darlaston, Wednesbury and Kings Hill were left with low pressure or no water at all due to an issue on Thursday evening.
Engineers from South Staffs Water were dispatched to the scene to investigate.
The cause of the issue has not yet been confirmed.
A spokesman for South Staffs Water said: "We're aware of an issue which is causing low pressure or no water for customers in Darlaston, Wednesbury and Kings Hill.
"We're currently on our way to investigate and aim to restore all supplies as quickly as possible.
"We're sorry for any inconvenience caused and thank you for your patience."