Northern Ireland Water has admitted that faults with newly-installed pipes caused a recent five-day break in supply to some householders.
Six hundred homes lost water in Kilkeel, Co Down, at the weekend, with 50 properties in the area still off supply for much of yesterday.
The problem was subsequently resolved and water restored to all homes by 5pm, according to a spokeswoman for NIW.
“All customers are back on supply and reservoirs returned to normal operating levels,” she said, adding that NIW “would like to thank customers for their patience during this period”.
The spokeswoman said a problem arose on Sunday after the section of a pipe on Head Road, Kilkeel — which was repaired two days previously — had burst.
Last week a burst main on the Head Road caused 3,000 homes to lose water supply.
NIW said the pipes used in the repair of that problem had been found to be faulty.
“This burst was as a result of the new pipework installed during the repair and not due to the workmanship of staff.
“NI Water will be carrying out investigations with the manufacturer of this pipework.”
Meanwhile, the company has also rejected criticism of how it communicated with customers affected by the problems.
UK Independence Party councillor Henry Reilly said he had been contacted by people trying to get information.
“It's like pulling teeth from NI Water to get information,” he said.
However, Liam Mulholland from NI Water said the company had been “extremely proactive” in getting information out.
“The website was updated five times one day last week, seven occasions another day and constantly over the weekend.” he said.