The major burst on the main pipe from the Eddie Fullerton Pollan Dam at Fahan has been repaired but the supply to some homes will not be fully restored until later this evening.
The burst has left thousands of homes without water throughout today but it's believed the main burst has been repaired and water will start flowing shortly, reaching all parts at an estimated time of 6 o'clock.
Supplies have been affected in Fahan, Burnfoot, Inch, Bridgend, Burt, Carrigans, Killea, Newtowncunningham, Manorcunningham and surrounding areas.
Some homes in the Killea, Carrigans and Newtowncunningham areas are now being temporarily supplied from Derry.
Cllr Jack Murray says despite relief in the area , something needs to be done to prevent future instances like this from happening again: