An electrical fault in a local pumping station lead to problems with the water supply in Preston, Chorley and Leyland on Saturday morning.
United Utilities say the problem is now fixed and water supplies should be back to normal in the PR3 postcode area.
A United Utilities spokesman said: “An electrical fault in the area has caused our local water pumping station to trip resulting in an interruption to the water supply.
“Our engineers have now rectified this and supplies should now be restored.
“We’re sorry for any inconvenience this may have caused.”