The project isn't due for completion until 5pm this evening.
Water supply to parts of Clane may be interrupted for much of today.
Repairs to a burst water-main begin at 10am.
Supply to Liffey Lawns, Abbey Court, Butterstream Drive, Butterstream Lawn and Prosperous Road could be implacted.
The project is due for completion at 5pm.
It could take up to three hours, after that, for the system to refill and for normal supply to resume.