Update 4pm: Fully replacing a mains pipe that burst triggering the water supply crisis in Louth and Meath could cost €3m and take 18 months, Irish Water has said.
A temporary repair has now been carried out on the damaged section of the pipe serving Staleen water treatment plant in Meath.
Engineers are testing to see it the patch holds.
While work on a more permanent repair will start next month, Irish Water has said the incident has highlighted a need to replace a 2.2km section of the main.
Irish Water managing director Jerry Grant said: "It's clear from the significant level of disruption and hardship endured by so many customers as a result of the burst on this high pressure main that its replacement must be a priority for Irish Water.
"A detailed programme for complete replacement will take a number of weeks to finalise and we will need to undertake detailed planning and design work before we can be confident around the exact time frame for this to happen.
"However, a preliminary view suggests a time frame of 18 months and a budget of 2-3 million euro will be needed to complete the work."
Up to 60,000 households and businesses have been affected by water shortages since the rupture on Friday.
Louth and Meath county councils continue to coordinate efforts to provide people with supplies.
Temporary water stations have been set up across both counties.
Water tankers and containers have also been mobilised across the country to replenish water supplies.
The Defence Forces, the Civil Defence, Louth and Meath fire services, Northern Ireland Water and a number of private sector companies have been involved in the distribution operation.
Community and voluntary groups, including the scouts, have also helped.
Update 11.04am: Irish Water says limited water supply is now available in Meath.
Works to repair a burst main in the North East got underway this morning and the utility says main urban centres in east and south east Meath will have some services during daylight hours today.
Update 9.58am: A specialist in public health has warned that the current water crisis is a significant risk to public health.
The warning comes as thousands of residents in the North East remain without safe water today.
Dr Peter Finnegan, a HSE specialist at the Department of Public Health in Navan, said: "People don't realise that we use about 50 gallons on average each day for various purposes - washing, cleaning, drinking etc. - so when our water supply is cut off, it's a big shock to the system," he said.
"When we haven't got clean, safe water it's quite a risk to public health."
Irish Water said that given the delicate nature of the pipe, engineers will have to work extremely slowly.
Sean Laffey of Irish Water says this particular watermain is unique in Ireland.
"The presure in the pipe is running at 18bar... that's essentially 18 times atmospheric pressure," he said.
"It is the highest pressure raw water main that we have in the country.
"I think the pipe was probably there longer than the engineers would have designed it for."
Irish Water is due to begin a fourth attempt to repair works to a burst water main in the North East today.
A specially engineered section of pipe has been manufactured in Belfast - however residents are being warned that it could be the weekend before supply is fully restored to 50,000 homes in Louth and Meath.
The utility is also warning that the pipe may rupture again once the water is turned back on.
There is growing concern that similar burst may happen across the country due to ageing infrastructure.
"The problem might just be past three metres down and the pipe might explode again," said Louth Councillor Kevin Callan.
"So I've said to them again today: 'You've no contingency plan' Over 200,000 people affected now in the entire North East region, and you've no resources to deal with this'."
Yesterday, Housing Minister Eoghan Murphy said that he is "quite confident" that the water outages in the North East will be fixed soon.
The Defence Forces have been deployed to help man the 43 tanks and 100 temporary water stations across Louth and Meath.
Minister Murphy has apologised to the tens of thousands of people affected by the crisis.
"I'm very sorry for all the people who have experienced these severe water shortages," he said.
"We've had them all over the country over the last number of years, we've had them in Dublin in my own constituency as well.
"We have the tankers out on the streets, people coming to get water so they can given their kids baths, people without water for more than a week, so I know how difficult it is for people when they face this situation."