Boil-water notices for more than 6,000 households will be lifted in the coming months, following completion of a treatment plant to remove dangerous bugs from drinking water.
Irish Water says an "interim" plant in Castlerea, Co Roscommon, has been completed and is subject to final quality checks from the HSE and Environmental Protection Agency (EPA) before water for 6,350 households in Roscommon is deemed safe to drink.
The plant was completed in January and is among 148 capital projects being overseen across the country by the utility.
The detail is contained in new data which shows Irish Water has overseen completion of 59 capital projects since it took control of the network in January last year.
These range from drainage schemes to water mains replacements and upgrades, along with delivery of new water and wastewater treatment plants.
Another 89 schemes are under way and due for completion from this month and out to 2017.
They include a new treatment plant at Swords in North Dublin, which will cater for 90,000 people and is due for completion next January, and an upgrade of the sewer network in the North Docklands which will allow for development of housing and office accommodation.
But Irish Water said a small number of projects had been delayed to complete final testing. They include:
Sludge treatment works at Ballymore Eustace in Kildare, which were due to be finished last month. The works are "largely completed".
A sewerage scheme in Youghal, Co Cork, was due for completion in February and is subject to snagging.
Replacement of water mains in Laois are also being verified, and were due for completion last month.
While construction works at the Castlerea plant have been completed, not until Irish Water proves it is operating as designed can boil-water notices be lifted.
Another treatment plant at Boyle has also been completed and, assuming it passes quality assurance tests, will result in supplies to an extra 12,000 people being given the all-clear.
Roscommon has been among the worst-affected counties in terms of drinking water quality.
More than 20,000 households are unable to drink the water from their taps.
The Castlerea plant was first proposed in February last year when Irish Water appeared before the Dáil environment committee. It said that options to "fast-track" a scheme for the town were being "assessed urgently" to remove boil-water notices affecting 6,350 people which had been in place for most of the previous four years.
Boil-water notices are only put in place after consultation with the HSE, which deems the supply to be dangerous to public health. Some 10 plants across Roscommon are due to be upgraded.
The update on Irish Water's capital plan will be published today. The costs of the projects will not be available for some weeks, as they must be scrutinised by the regulator.