A boil water notice for around 600,000 people in the greater Dublin area remains in place for now, as officials prepare to examine the results of an audit at the affected treatment plant.
The warning was issued earlier this week following issues at the Leixlip Water Treatment Plant.
Today, the Environmental Protection Agency (EPA) conducted an audit of the plant, with Irish Water, Fingal County Council and the HSE also present.
Officials will now assess the details of the audit, and the various groups will meet tomorrow to discuss the preliminary findings.
Results of a second water sample are also expected tomorrow, after a sample earlier in the week was found to be 'satisfactory'.
Yvonne Harris, Irish Water's head of customer operations, said the utility understands the impact of the boil water notice on the hundreds of thousands of people affected.
She said: "It is our priority to work with the HSE and the EPA to get the boil water notice lifted as quickly as it is safe to do so.
“Working with our partners Fingal County Council we are endeavouring to ensure that the EPA and HSE can be confident in the water quality and in the workings of the plant."
The ongoing notice covers parts of Fingal, areas in Dublin City Council, parts of South Dublin County Council, parts of Kildare and Dunboyne in Meath.
It means tap water in those areas must be boiled for the likes of drinking, making ice, preparing salads / food that will not be cooked, and brushing teeth.
The warning was issued amid fears the water may contain cysts of cryptosporidium and giardia - which the HSE says "may cause gastrointestinal infections with symptoms such as diarrhoea and stomach cramps".
It has seen people in affected areas stock up on bottled water, with many supermarket water shelves empty yesterday as result.