Uisce Éireann has begun carrying out essential repair work on the supply system in the Greater Dublin Area.
It comes as a pipeline supplying one third of the region’s drinking water is at risk of failure and was turned off at 11pm last night for 28 hours to enable complex repairs to take place.
Uisce Éireann released a map showing areas where supply may be disrupted
The work will continue into the early hours of tomorrow morning.
Customers in the greater Dublin area region, which includes parts of Co Wicklow and Co Kildare, are urged to use water only when necessary over the bank holiday weekend.
The purpose of the work is to prevent a catastrophic failure that would lead to widescale outages and disturbance if the damaged watermains were left to rupture.
Head of Water Operations at Uisce Éireann Margaret Attridge asked people to hold off on filling baths, car washing, power hosing, window washing and filling paddling pools.
She added: “Reducing your water use will help maintain or extend water supply during the repairs, for yourself and, importantly, for vulnerable and high-risk users including hospitals and care homes.”