Update 6pm: Irish Water has apologised after a second major water pipe burst in just over a week, cutting off supply to up 10,000 households and businesses.
The pipe has since been fixed and Irish Water said everyone's supply should be back tonight.
The utility provider said it "apologises for the inconvenience caused by this incident and thanks customers for their patience and cooperation".
Among those affected are a grandfather and grandmother who have been forced to move into temporary accommodation after the burst pipe flooded their family home of 50 years for the second time in 18 months.
James Murtagh, 80, and 72-year-old Joan had only moved back into their home in Proudstown outside Navan nine months ago following major repairs to the property after the same pipe burst and flooded their home just days before Christmas in 2015.
The couple, their daughter Sarah, 44, and 16-year-old granddaughter had to escape from the house through a window on Monday night after water gushed into the property.
It comes less than two weeks after a burst water main left around 60,000 customers across Louth and Meath without water for several days.
"My parent's aren't fit for this," said Ms Murtagh. "My mum is so angry.
"The main water pipe for Navan is outside our house and on December 22, 2015, it burst and the whole house was completely flooded.
"Mum and dad were out of house for nine months. All the foundations had to be dug up again."
She added: "Last night my daughter came running in and said there was water coming into bathroom. I went in and saw all this dirty water.
"I went to the kitchen and when I opened the door I saw the water getting faster and faster and rising and rising.
"I got my mum and dad and we had to go out the window because we couldn't open the doors or it all would have come flooding in.
"We don't know how badly damaged the house is at the minute but we have been advised we could be out for three to six months."
Repairs on the burst pipe that feeds water into Navan have now been completed.
Full water supply to the town and surrounding areas is expected to be restored on Tuesday evening.
Irish Water had placed water tankers on standby to replenish Our Lady's Hospital in Navan in case its water storage ran out.
In July around 60,000 households and businesses in the Drogheda area were left without water for almost a week after a main burst at the Staleen Water Treatment Plant.
Update 4.30pm: Water has begun to return to homes and businesses in Navan hit by today's outages.
A burst pipe has been repaired and Irish Water say everyone's supply should return this evening.
As many as 10,000 customers were left without water for the majority of the day.
Local Fianna Fáil TD Shane Cassells says there needs to be urgent investment to stop incidents like this from happening.
Update 1.21pm: A pipe which burst outside Navan, Co Meath this morning also burst had done so before, flooding some local homes, it has emerged.
Up to 10,000 customers could experience disruption to their water supply this afternoon.
It has already caused flooding one home next to the pipe.
“We’re just about a year in now from when it happened [last],” said local resident Joan.
When asked if she had to leave her house again, she said: “Oh we are, we have to, because everything has to come up now again.
“It was a huge upheaval last time, because the water down went into the floors – it’s an old house.”
Many local businesses in the area are without water, including the Big O pub, which has been boiling water to make the tea.
Local Councillor Paddy Meade said that something needs to be done about water leaks, after 70,000 people in the area were left without water last week.
“It’s having a massive impact on businesses,” he said. “business owners are ringing me, and other Councillors saying: ‘Look, we pay rates, we pay for our water, this isn’t a case of the public not paying for water, we are businesses that do pay for water, and we expect a service’.”
Irish Water have said that repairs are going well, and should be completed this afternoon.
Up to 10,000 customers could be without water after a major pipe burst in Co Meath.
It happened on the Proudstown Road in Navan, which has been closed to allow for repair work.
This is the second serious incident after 70,000 people in the North East were recently left without water for almost a week.
Irish Water say between 5-10,000 customers are affected.
They say there is some water still in the network, so many may not be experiencing a full outage yet, but may have reduced pressure.
Tankers have been put on standby to replenish storage tanks in Our Lady's Hospital in Navan in case their water runs short.
Irish Water say crews have been on site since this morning and the repair works are going well, with supply expected to be restored by early afternoon.