Draperstown: Air lock causes water problems for 150 homes
Up to 150 homes in Draperstown, County Londonderry, are without water because of an ongoing air locking problem, NI Water has said.
The company said it has "multiple staff" in the area trying to fix it.
It added alternative water supplies were being made available to affected customers.
Patricia Gray, whose family lives in the affected area, told the BBC they were having to use melted snow to get water.
"This is the second full day we've had to use melted snow," she said.
"They keep telling us it'll go back on, but they keep pushing it back.
"We're having to use melted snow to wash our faces. There's not a bottle of water to be found in the area."
NI Water chief executive Sara Venning has apologised for the situation and told BBC Northern Ireland's Evening Extra programme that she was not able at this stage to say when the Gray family's water supply would be restored.
"Unfortunately because of the industrial action, the system has drained," she said.
"As we have filled the system back up again, we are experiencing an air lock.
"Our normal emergency staff have left for the weekend, they have refused to give us their services, we are engaging as much additional resource as we can find.
"Therefore I do not have that certainty and I apologise for that."
It is understood there have also been problems with water supply for some residents at Bardahessiagh Road, outside Pomeroy in County Tyrone.
One resident said she had not received water supply to her house since Wednesday morning.
Earlier, in a statement, NI Water said they hoped the issue would be resolved later on Friday and said alternative water supplies were available.
A spokesperson said: "An alternative water supply is now available from our plastic water tanks which are located at 82 Sixtowns Road, Draperstown.
"They are located in the lay-by opposite the primary school. Customers will need to bring their own containers to collect water from the tanks. Customers should boil the water before use.
"NI Water fully recognises this is a frustrating experience for our customers, and can assure them we are doing everything possible to restore water supplies as quickly as possible."
NI Water said it was aware of a small number of customers in the Pomeroy area still being "intermittently affected by airlocks" which were causing disruptions to supply. It said it had staff deployed in the area to address the problem.
Last week, almost 10,000 homes in Counties Fermanagh and Tyrone had their water supplies disrupted after a pump at a treatment plant broke down.