Irish Water, which operates three main water supply lines, has been forced to apologise after some users were unable to access their water.
The Irish Independent has obtained emails from the company, showing the company was aware of a number of problems and responding quickly.
In one email dated November 29, 2016, the company wrote: “Due to a lack of water supply we are advising that all customers with water piping and fittings not in working order should have them replaced as soon as possible.”
Water pipes have been replaced on a number sites across Ireland.
It is not clear how many customers were affected by the issue.
Water pipes in Dublin have been inspected by water safety experts and they have been tested for the presence of nitrates.
Nitrates can cause breathing difficulties for people with lung problems, including people with asthma.
Irish Water has also apologised for the issue, saying: “We apologise unreservedly to those customers that were not able to access the water they need to continue using the water system.”
Water is piped through a pipe to a home, which is then connected to a distribution system to a point where it can be delivered to the home.
Irish Health Minister Simon Harris said on Thursday that he had “a number of people” in contact with Irish Water about the issue and was taking action.
He said he would be meeting with the company and others to make sure that all issues were addressed.
“I’m aware that there are a number people that have been very affected by this,” he said.
He added: “I am going to have a number meetings with those affected and will be taking appropriate action to make it right.”